The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Walter S Leal - One of the best experts on this subject based on the ideXlab platform.
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Pheromone discrimination by a ph tuned polymorphism of the bombyx mori Pheromone Binding Protein
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Fred F. Damberger, Walter S Leal, Yuko Ishida, Erich Michel, Kurt WuthrichAbstract:The Bombyx mori Pheromone-Binding Protein (BmorPBP) is known to adopt two different conformations. These are BmorPBPA, where a regular helix formed by the C-terminal dodecapeptide segment, α7, occupies the ligand-Binding cavity, and BmorPBPB, where the Binding site is free to accept ligands. NMR spectra of delipidated BmorPBP solutions at the physiological pH of the bulk sensillum lymph near pH 6.5 show only BmorPBPA, and in mixtures, the two species are in slow exchange on the chemical shift frequency scale. This equilibrium has been monitored at variable pH and ligand concentrations, demonstrating that it is an intrinsic property of BmorPBP that is strongly affected by pH variation and ligand Binding. This polymorphism tunes BmorPBP for optimal selective Pheromone transport: Competition between α7 and lipophilic ligands for its Binding cavity enables selective uptake of bombykol at the pore endings in the sensillum wall, whereas compounds with lower Binding affinity can only be bound in the bulk sensillum lymph. After transport across the bulk sensillum lymph into the lower pH area near the dendritic membrane surface, bombykol is ejected near the receptor, whereas compounds with lower Binding affinity are ejected before reaching the olfactory receptor, rendering them susceptible to degradation by enzymes present in the sensillum lymph.
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crystallographic observation of ph induced conformational changes in the amyelois transitella Pheromone Binding Protein atrapbp1
PLOS ONE, 2013Co-Authors: Eric Di Luccio, Walter S Leal, Yuko Ishida, David K WilsonAbstract:The navel orangeworm, Amyelois transitella is a major agricultural pest causing large losses in a variety of tree crops. Control of this insect pest may be achieved by interfering with olfactory pathways to block detection of female-produced sex Pheromones and consequently, disrupt mating. The first component of this pathway is the Pheromone-Binding Protein AtraPBP1, which recognizes the Pheromone and presents it to the odorant receptor housed in a sensory neuron of the male antennae. Release of the ligand depends on a pH-induced conformational change associated with the acidity of the membrane surface. To characterize this conformational change and to understand how Pheromones bind, we have determined the high resolution crystal structures of AtraPBP1 in complex with two main constituents of the sex Pheromone, i.e., (11Z,13Z)-hexadecadienal and (11Z,13Z)-hexadecadienol. Comparison with the structure of the unliganded form demonstrates a large ∼90° movement of the C-terminal helix which is observed in other Pheromone- or odorant-Binding Proteins accompanied by an unpredicted 37° displacement of the N-terminal helix. Molecular dynamic trajectories suggest that the conformational change of the α1 helix facilitates the movement of the C-terminal helix.
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Dynamic Conformational Equilibria in the Physiological Function of the Bombyx mori Pheromone-Binding Protein
Journal of molecular biology, 2011Co-Authors: Erich Michel, Donghan Lee, Fred F. Damberger, Walter S Leal, Yuko Ishida, Francesco Fiorito, Kurt WuthrichAbstract:Abstract The Bombyx mori Pheromone-Binding Protein (BmorPBP) undergoes a pH-dependent conformational transition from a form at basic pH, which contains an open cavity suitable for ligand Binding (BmorPBP B ), to a form at pH 4.5, where this cavity is occupied by an additional helix (BmorPBP A ). This helix α7 is formed by the C-terminal dodecapeptide 131–142, which is flexibly disordered on the Protein surface in BmorPBP B and in its complex with the Pheromone bombykol. Previous work showed that the ligand-Binding cavity cannot accommodate both bombykol and helix α7. Here we further investigated mechanistic aspects of the physiologically crucial ejection of the ligand at lower pH values by solution NMR studies of the variant Protein BmorPBP(1–128), where the C-terminal helix-forming tetradecapeptide is removed. The NMR structure of the truncated Protein at pH 6.5 corresponds closely to BmorPBP B . At pH 4.5, BmorPBP(1–128) maintains a B-type structure that is in a slow equilibrium, on the NMR chemical shift timescale, with a low-pH conformation for which a discrete set of 15 N– 1 H correlation peaks is NMR unobservable. The full NMR spectrum was recovered upon readjusting the pH of the Protein solution to 6.5. These data reveal dual roles for the C-terminal tetradecapeptide of BmorPBP in the mechanism of reversible Pheromone Binding and transport, where it governs dynamic equilibria between two locally different Protein conformations at acidic pH and competes with the ligand for Binding to the interior cavity.
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extrusion of the c terminal helix in navel orangeworm moth Pheromone Binding Protein atrapbp1 controls Pheromone Binding
Biochemical and Biophysical Research Communications, 2011Co-Authors: Walter S Leal, James B AmesAbstract:The navel orangeworm, Amyelois transitella (Walker), is an agricultural insect pest that can be controlled by disrupting male–female communication with sex Pheromones, a technique known as mating disruption. Insect Pheromone-Binding Proteins (PBPs) provide fast transport of hydrophobic Pheromones through aqueous sensillar lymph and promote sensitive delivery of Pheromones to receptors. Here we present a mutational analysis on a PBP from A. transitella (AtraPBP1) to evaluate how the C-terminal helix in this Protein controls Pheromone Binding as a function of pH. Pheromone binds tightly to AtraPBP1 at neutral pH, but the Binding is much weaker at pH below 5. Deletion of the entire C-terminal helix (residues 129–142) causes more than 100-fold increase in Pheromone-Binding affinity at pH 5 and only a 1.5-fold increase at pH 7. A similar pH-dependent increase in Pheromone Binding is also seen for the H80A/H95A double mutant that promotes extrusion of the C-terminal helix by disabling salt bridges at each end of the helix. The single mutants (H80A and H95A) also exhibit Pheromone Binding at pH below 5, but with ∼2-fold weaker affinity. NMR and circular dichroism data demonstrate a large overall structural change in each of these mutants at pH 4.5, indicating an extrusion of the C-terminal helix that profoundly affects the overall structure of the low pH form. Our results confirm that sequestration of the C-terminal helix at low pH as seen in the recent NMR structure may serve to block Pheromone Binding. We propose that extrusion of these C-terminal residues at neutral pH (or by the mutations in this study) exposes a hydrophobic cleft that promotes high affinity Pheromone Binding.
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nmr structure of navel orangeworm moth Pheromone Binding Protein atrapbp1 implications for ph sensitive Pheromone detection
Biochemistry, 2010Co-Authors: Josep Rayo, Walter S Leal, Yuko Ishida, James B AmesAbstract:The navel orangeworm, Amyelois transitella (Walker), is an agricultural insect pest that can be controlled by disrupting male−female communication with sex Pheromones, a technique known as mating disruption. Insect Pheromone-Binding Proteins (PBPs) provide fast transport of hydrophobic Pheromones through the aqueous sensillar lymph and promote sensitive delivery of Pheromones to receptors. Here we present the three-dimensional structure of a PBP from A. transitella (AtraPBP1) in solution at pH 4.5 determined by nuclear magnetic resonance (NMR) spectroscopy. Pulsed-field gradient NMR diffusion experiments, multiangle light scattering, and 15N NMR relaxation analysis indicate that AtraPBP1 forms a stable monomer in solution at pH 4.5 in contrast to forming mostly dimers at pH 7. The NMR structure of AtraPBP1 at pH 4.5 contains seven α-helices (α1, L8−L23; α2, D27−F36; α3, R46−V62; α4, A73−M78; α5, D84−S100; α6, R107−L125; α7, M131−E141) that adopt an overall main-chain fold similar to that of PBPs found in ...
Zhen Tian - One of the best experts on this subject based on the ideXlab platform.
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structural evidence for Pheromone discrimination by the Pheromone Binding Protein 3 from plutella xylostella
International Journal of Biological Macromolecules, 2021Co-Authors: Jiyuan Liu, Zhen Tian, Tong Zhou, Shichang ChengAbstract:Insect Pheromone Binding Proteins (PBPs) are believed to have a high degree of Pheromone selectivity, acting as the first filter to discriminate specific Pheromones from other volatile compounds. Herein, we provide evidence using homology-based model for the Pheromone discrimination of Plutella xylostella Pheromone Binding Protein 3 (PxPBP3). Combining molecular dynamics simulations and in vitro Binding assays, two dominant sites are determined to be essential for the PxPBP3 to discriminate (Z)-11-hexadecenyl acetate (Hexadecenyl) from (Z)-11-hexadecenal (Hexadecenal). As the first key site for Pheromone discrimination, Arg111 is indispensable to the PxPBP3-Hexadecenyl interaction. However, its importance in the Binding of Hexadecenal to PxPBP3 is greatly reduced. A second site where Pheromone discrimination occurs is a small loop (residues 34-38) in PxPBP3. It is shown that the hydrophobic strength provided by three hydrophobic residues (Phe34, Tyr37, and Trp38) in the small loop is significantly biased in the two complexes formed by PxPBP3 and the two Pheromones. The discrimination capacity of PxPBP3 indicates that the P. xylostella Pheromones may not share the same peri-receptor pathway, although they both show high affinity to PxPBP3.
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structure dynamics reveal key residues essential for the sense of 1 dodecanol by cydia pomonella Pheromone Binding Protein 2 cpompbp2
Pest Management Science, 2020Co-Authors: Zhen Tian, Tong Zhou, Jiyuan LiuAbstract:Background Cydia pomonella, a worldwide quarantine fruit pest, causes great damage to fruit production every year. Sex Pheromone-mediated control of C. pomonella has been widely used. As an indispensable ingredient of commercial sex attractants, 1-dodecanol (Dod) works to synergize the effect of codlemone in attracting male moths of C. pomonella. The interactions between Dod and its transporter Protein, C. pomonella Pheromone-Binding Protein 2 (CpomPBP2), provide inspiration for chemical optimizations to improve the synergistic effects of Dod. Results In this research, molecular simulations and biological verifications were used in combination to uncover key residues in CpomPBP2 essential for sensing Dod. After performing 150 ns molecular dynamics (MD) simulations, the C1-C12 chain of Dod was found to be locked by the van der Waals energy contributed by the hydrophobic residues Phe12, Leu68, and Ile113, whereas the -OH part of Dod was anchored by the H-bond derived from Glu98 and the salt-bridge derived from Arg109. Because of the importance of these two electrostatic interactions, Glu98 and Arg109 were further verified as key residues in determining the Binding affinity between Dod and CpomPBP2. In addition, interactions unfavorable to the Binding of Dod were described. Conclusion The research detailed the discovery of key residues involved in CpomPBP2-Dod interactions. Our results provide guidance and caution for the prospective discovery, optimization, and design of novel chemicals with a similar or stronger synergistic effect to codlemone in controlling C. pomonella.
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Structural Insights into Two Representative Conformations of the Complex Formed by Grapholita molesta (Busck) Pheromone Binding Protein 2 and Z-8-Dodecenyl Acetate.
Journal of agricultural and food chemistry, 2019Co-Authors: Zhen Tian, Yijia Xing, Jiyuan LiuAbstract:Grapholita molesta is a notorious fruit borer globally, causing severe damage to fruit production. To control the pest, one commonly used mean is Pheromone-mediated management. As an important sex Pheromone, Z-8-dodecenyl acetate (Z8–12: Ac), is often coformulated with other active ingredients to regulate the behavior of G. molesta. To uncover its interactions with G. molesta Pheromone Binding Protein 2 (GmolPBP2) is used to help develop insect attractants. During 200 ns molecular dynamics simulations, two representative conformations of the GmolPBP2-Z8–12: Ac complex are selected. Conformation II at the time of 14–106 ns is dominantly maintained by the hydrophobic interactions and hydrogen bond. In Conformation I, which lasts from 106 to 200 ns, the hydrophobic interactions are enhanced while the hydrogen bond is quite weakened, due to the formation of a more sophisticated hydrophobic Binding pocket and the enlargement of hydrogen bond distance. Taking the two conformations as a whole, the affinity betwe...
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key residues involved in the interaction between cydia pomonella Pheromone Binding Protein 1 cpompbp1 and codlemone
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Zhen Tian, Jiyuan Liu, Yalin ZhangAbstract:Codlemone exhibited high affinity to CpomPBP1; studying their Binding mode can provide insights into the rational design of active semiochemicals. Our findings suggested that residues including Phe12, Phe36, Trp37, Ile52, Ile 94, Ala115, and Phe118 were favorable to the Binding of codlemone to CpomPBP1, whereas residues providing unfavorable contributions such as Ser56 were negative to the Binding. van der Waals energy and electrostatic energy, mainly derived from the side chains of favorable residues, contributed most to the formation and stability of the CpomPBP1–codlemone complex. Of the residues involved in the interaction between CpomPBP1 and codlemone, Phe12 and Trp37, the mutation of which into Ala caused a significant decrease of CpomPBP1 Binding ability, were two key residues in determining the Binding affinity of codlemone to CpomPBP1. This study shed light on discovering novel active semiochemicals as well as facilitating chemical modification of lead semiochemicals.
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structural insights into cydia pomonella Pheromone Binding Protein 2 mediated prediction of potentially active semiochemicals
Scientific Reports, 2016Co-Authors: Zhen Tian, Jiyuan Liu, Yalin ZhangAbstract:Given the advantages of behavioral disruption application in pest control and the damage of Cydia pomonella, due progresses have not been made in searching active semiochemicals for codling moth. In this research, 31 candidate semiochemicals were ranked for their Binding potential to Cydia pomonella Pheromone Binding Protein 2 (CpomPBP2) by simulated docking, and this sorted result was confirmed by competitive Binding assay. This high predicting accuracy of virtual screening led to the construction of a rapid and viable method for semiochemicals searching. By reference to Binding mode analyses, hydrogen bond and hydrophobic interaction were suggested to be two key factors in determining ligand affinity, so is the length of molecule chain. So it is concluded that semiochemicals of appropriate chain length with hydroxyl group or carbonyl group at one head tended to be favored by CpomPBP2. Residues involved in Binding with each ligand were pointed out as well, which were verified by computational alanine scanning mutagenesis. Progress made in the present study helps establish an efficient method for predicting potentially active compounds and prepares for the application of high-throughput virtual screening in searching semiochemicals by taking insights into Binding mode analyses.
Kurt Wuthrich - One of the best experts on this subject based on the ideXlab platform.
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Pheromone discrimination by a ph tuned polymorphism of the bombyx mori Pheromone Binding Protein
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Fred F. Damberger, Walter S Leal, Yuko Ishida, Erich Michel, Kurt WuthrichAbstract:The Bombyx mori Pheromone-Binding Protein (BmorPBP) is known to adopt two different conformations. These are BmorPBPA, where a regular helix formed by the C-terminal dodecapeptide segment, α7, occupies the ligand-Binding cavity, and BmorPBPB, where the Binding site is free to accept ligands. NMR spectra of delipidated BmorPBP solutions at the physiological pH of the bulk sensillum lymph near pH 6.5 show only BmorPBPA, and in mixtures, the two species are in slow exchange on the chemical shift frequency scale. This equilibrium has been monitored at variable pH and ligand concentrations, demonstrating that it is an intrinsic property of BmorPBP that is strongly affected by pH variation and ligand Binding. This polymorphism tunes BmorPBP for optimal selective Pheromone transport: Competition between α7 and lipophilic ligands for its Binding cavity enables selective uptake of bombykol at the pore endings in the sensillum wall, whereas compounds with lower Binding affinity can only be bound in the bulk sensillum lymph. After transport across the bulk sensillum lymph into the lower pH area near the dendritic membrane surface, bombykol is ejected near the receptor, whereas compounds with lower Binding affinity are ejected before reaching the olfactory receptor, rendering them susceptible to degradation by enzymes present in the sensillum lymph.
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Dynamic Conformational Equilibria in the Physiological Function of the Bombyx mori Pheromone-Binding Protein
Journal of molecular biology, 2011Co-Authors: Erich Michel, Donghan Lee, Fred F. Damberger, Walter S Leal, Yuko Ishida, Francesco Fiorito, Kurt WuthrichAbstract:Abstract The Bombyx mori Pheromone-Binding Protein (BmorPBP) undergoes a pH-dependent conformational transition from a form at basic pH, which contains an open cavity suitable for ligand Binding (BmorPBP B ), to a form at pH 4.5, where this cavity is occupied by an additional helix (BmorPBP A ). This helix α7 is formed by the C-terminal dodecapeptide 131–142, which is flexibly disordered on the Protein surface in BmorPBP B and in its complex with the Pheromone bombykol. Previous work showed that the ligand-Binding cavity cannot accommodate both bombykol and helix α7. Here we further investigated mechanistic aspects of the physiologically crucial ejection of the ligand at lower pH values by solution NMR studies of the variant Protein BmorPBP(1–128), where the C-terminal helix-forming tetradecapeptide is removed. The NMR structure of the truncated Protein at pH 6.5 corresponds closely to BmorPBP B . At pH 4.5, BmorPBP(1–128) maintains a B-type structure that is in a slow equilibrium, on the NMR chemical shift timescale, with a low-pH conformation for which a discrete set of 15 N– 1 H correlation peaks is NMR unobservable. The full NMR spectrum was recovered upon readjusting the pH of the Protein solution to 6.5. These data reveal dual roles for the C-terminal tetradecapeptide of BmorPBP in the mechanism of reversible Pheromone Binding and transport, where it governs dynamic equilibria between two locally different Protein conformations at acidic pH and competes with the ligand for Binding to the interior cavity.
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structural basis of ligand Binding and release in insect Pheromone Binding Proteins nmr structure of antheraea polyphemus pbp1 at ph 4 5
Journal of Molecular Biology, 2007Co-Authors: Fred F. Damberger, Kurt Wuthrich, Walter S Leal, Yuko IshidaAbstract:Abstract The NMR structure of the Antheraea polyphemus Pheromone-Binding Protein 1 at pH 4.5, ApolPBP1 A , was determined at 20 °C. The structure consists of six α-helices, which are arranged in a globular fold that encapsulates a central helix α7 formed by the C-terminal polypeptide segment 131–142. The 3D arrangement of these helices is anchored by the three disulfide bonds 19–54, 50–108 and 97–117, which were identified by NMR. Superposition of the ApolPBP1 A structure with the structure of the homologous Pheromone-Binding Protein of Bombyx mori at pH 4.5, BmorPBP A , yielded an rmsd of 1.7 A calculated for the backbone heavy-atoms N, C α and C′ of residues 10–142. In contrast, the present ApolPBP1 A structure is different from a recently proposed molecular model for a low-pH form of ApolPBP1 that does not contain the central helix α7. ApolPBP1 exhibits a pH-dependent transition between two different globular conformations in slow exchange on the NMR chemical shift timescale similar to BmorPBP, suggesting that the two Proteins use the same mechanism of ligand Binding and ejection. The extensive sequence homology observed for Pheromone-Binding Proteins from moth species further implies that the previously proposed mechanism of ligand ejection involving the insertion of a C-terminal helix into the Pheromone-Binding site is a general feature of Pheromone signaling in moths.
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NMR structure of the unliganded Bombyx mori Pheromone-Binding Protein at physiological pH
FEBS Letters, 2002Co-Authors: Donghan Lee, Fred F. Damberger, Guihong Peng, Reto Horst, Larisa Nikonova, Peter Guntert, Walter S Leal, Kurt WuthrichAbstract:The nuclear magnetic resonance structure of the unliganded Pheromone-Binding Protein (PBP) from Bombyx mori at pH above 6.5, BmPBPB, consists of seven helices with residues 3–8, 16–22, 29–32, 46–59, 70–79, 84–100, and 107–124, and contains the three disulfide bridges 19–54, 50–108, and 97–117. This polypeptide fold encloses a large hydrophobic cavity, with a sufficient volume to accommodate the natural ligand bombykol. The polypeptide folds in free BmPBPB and in crystals of a BmPBP–bombykol complex are nearly identical, indicating that the B-form of BmPBP in solution represents the active conformation for ligand Binding.
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nmr characterization of a ph dependent equilibrium between two folded solution conformations of the Pheromone Binding Protein from bombyx mori
Protein Science, 2000Co-Authors: Fred F. Damberger, Guihong Peng, Reto Horst, Larisa Nikonova, Walter S Leal, Kurt WuthrichAbstract:NMR spectroscopic changes as a function of pH in solutions of the Pheromone-Binding Protein of Bombyx mori (BmPBP) show that BmPBP undergoes a conformational transition between pH 4.9 and 6.0. At pH below 4.9 there is a single "acid form" (A), and a homogeneous "basic form" (B) exists at pH above 6.0. Between pH 5 and 6, BmPBP exists as a mixture of A and B in slow exchange on the NMR chemical shift time scale, with the transition midpoint at pH 5.4. The form B has a well-dispersed NMR spectrum, indicating that it represents a more structured, "closed" conformation than form A, which has a significantly narrower chemical shift dispersion. Conformational transitions of the kind observed here may explain heterogeneity reported for a variety of odorant-Binding Proteins, and it will be of interest to further investigate possible correlations with pH-dependent regulation of ligand Binding and release in the biological function of this class of Proteins.
Jurgen Krieger - One of the best experts on this subject based on the ideXlab platform.
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a Pheromone Binding Protein mediates the bombykol induced activation of a Pheromone receptor in vitro
Chemical Senses, 2006Co-Authors: Ewald Grossewilde, Ales Svatos, Jurgen KriegerAbstract:The enormous capacity of the male silkmoth Bombyx mori in recognizing and discriminating bombykol and bombykal is based on distinct sensory neurons in the antennal sensilla hairs. The hydrophobic pheromonal compounds are supposed to be ferried by soluble Pheromone-Binding Proteins (PBPs) through the sensillum lymph toward the receptors in the dendritic membrane. We have generated stable cell lines expressing the candidate Pheromone receptors of B. mori, BmOR-1 or BmOR-3, and assessed their responses to hydrophobic Pheromone compounds dissolved by means of dimethyl sulfoxide. BmOR-1–expressing cells were activated by bombykol but also responded to bombykal, whereas cells expressing BmOR-3 responded to bombykal only. In experiments employing the B. mori PBP, no organic solvent was necessary to mediate an activation of BmOR-1 by bombykol, indicating that the PBP solubilizes the hydrophobic compound. Furthermore, the employed PBP selectively mediated a response to bombykol but not to bombykal, supporting a ligand specificity of PBPs. This study provides evidence that both distinct Pheromone receptors and PBPs play an important role in insect Pheromone recognition.
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Species-specific pheromonal compounds induce distinct conformational changes of Pheromone Binding Protein subtypes from Antheraea polyphemus.
Invertebrate neuroscience : IN, 2002Co-Authors: Claudia Mohl, Heinz Breer, Jurgen KriegerAbstract:We have investigated the structural features of three Pheromone Binding Protein (PBP) subtypes from Antheraea polyphemus and monitored possible changes induced upon interaction with the Antheraea pheromonal compounds 4E,9Z-14:Ac [(E4,Z9)-tetradecadienyl-1-acetate], 6E,11Z-16:Ac [(E6,Z11)-hexadecadienyl-1-acetate], and 6E,11Z-16:Al [(E6,Z11)-hexadecadienal]. Circular dichroism and second derivative UV-difference spectroscopy data demonstrate that the structure of subtype PBP1 significantly changes upon Binding of 4E,9Z-14:Ac. The related 6E,11Z-16:Ac was less effective and 6E,11Z-16:Al showed only a small effect. In contrast, in subtype PBP2 pronounced structural changes were only induced by the 6E,11Z-16:Al, and the subtype PBP3 did not show any considerable changes in response to the pheromonal compounds. The UV-spectroscopic data suggest that histidine residues are likely to be involved in the ligand-induced structural changes of the Proteins, and this notion was confirmed by site-directed mutagenesis experiments. These results demonstrate that appropriate ligands induce structural changes in PBPs and provide evidence for ligand specificity of these Proteins.
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probing a Pheromone Binding Protein of the silkmoth antheraea polyphemus by endogenous tryptophan fluorescence
Insect Biochemistry and Molecular Biology, 2002Co-Authors: Stefanie Bette, Heinz Breer, Jurgen KriegerAbstract:One subtype of the Pheromone Binding Proteins of the silkmoth Antheraea polyphemus (ApolPBP1) has been analysed exploiting the two endogenous tryptophan residues as fluorescent probe. The intrinsic fluorescence exhibited a rather narrow spectrum with a maximum at 336 nm. Site-directed mutagenesis experiments revealed that one of the tryptophan residues (Trp37) is located in a hydrophobic environment whereas Trp127 is more solvent exposed, as was predicted modeling the ApolPBP1 sequence on the proposed structure of the Bombyx mori Pheromone Binding Protein. Monitoring the interaction of ApolPBP1 as well as its Trp mutants with the three species-specific Pheromone compounds by recording the endogenous fluorescence emission revealed profound differences; whereas (E6,Z11)-hexadecadienal induced a dose-dependent quenching of the fluorescence, both (E6,Z11)-hexadecadienyl-1-acetate and (E4,Z9)-tetradecadienyl-1-acetate elicited an augmentation of the endogenous fluorescence. These data indicate that although ApolPBP1 can bind all three Pheromones, there are substantial differences concerning their interaction with the Protein, which may have important functional implications.
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detection and removal of an artefact fatty acid from the Binding site of recombinant bombyx mori Pheromone Binding Protein
Chemical Senses, 2001Co-Authors: Neil J Oldham, Jurgen Krieger, Heinz Breer, Ales SvatosAbstract:Recombinant Bombyx mori Pheromone-Binding Protein (PBP), purified from an Escherichia coli expression system, has been found to contain (11Z)-octadecenoic acid (cis-vaccenic acid) as an artefact ligand. An efficient delipidation procedure is described to overcome what would appear to be a general problem with recombinant lepidopteran PBPs.
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odorant Binding Proteins of heliothis virescens
Insect Biochemistry and Molecular Biology, 1993Co-Authors: Jurgen Krieger, K Raming, Heinz Weiβ, Heinz BreerAbstract:: cDNA clones coding for three different Binding Proteins were isolated from an antennal library of Heliothis virescens. The deduced amino acid sequences showed only moderate homology to each other but shared several common structural features. Based on a comparison with the predicted primary structures of antennal Binding Proteins from different moth species, one of the clones (Hel-1) was found to encode a Pheromone Binding Protein, whereas the two others (Hel-10 and -11) encode general odorant Binding Proteins.
Smita Mohanty - One of the best experts on this subject based on the ideXlab platform.
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Pheromone Perception: Mechanism of the Reversible Coil-Helix Transition in Antheraea polyphemus Pheromone-Binding Protein 1.
Biochemistry, 2019Co-Authors: Suman Mazumder, Bharat P. Chaudhary, Salik R. Dahal, Omar Al-danoon, Smita MohantyAbstract:Pheromone-Binding Protein (PBP) in male moth antennae transports Pheromone to the olfactory receptor neuron by undergoing a pH-dependent conformational switch, from PBPB at higher pH to PBPA at lower pH, associated with ligand Binding and release, respectively. The characteristic feature of the dramatic Protein switch is the pH-dependent reversible coil-helix transition of the C-terminus. In the PBPB conformation at pH >6.0, the C-terminus is exposed to the solvent as a coil while the ligand occupies the hydrophobic pocket. However, in the PBPA conformation at acidic pH, the C-terminus switches to a helix and releases the ligand by outcompeting it for the hydrophobic pocket. In Antheraea polyphemus PBP1 (ApolPBP1), the C-terminus (P129-V142) is composed predominantly of hydrophobic residues except for three strategically located acidic residues: Asp132, Glu137, and Glu141. Here, we report for the first time on the consequences of the mutation of one or more acidic residues in the pH-driven reversible coil-helix transition of the ApolPBP1 C-terminus through biophysical characterization. Mutation of any single acidic residue in the C-terminus to its neutral counterpart destabilizes the helix formation at lower pH; these mutants exist as a mixture of both conformations. However, mutation of the two terminal acidic residues together knocks out the Protein switch and adversely affects both ligand Binding and release functions. Thus, these mutant Proteins remain in the open (PBPB) conformation at all pH levels.
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ligand Binding turns moth Pheromone Binding Protein into a ph sensor effect on the antheraea polyphemus pbp1 conformation
Journal of Biological Chemistry, 2009Co-Authors: Uma V. Katre, Suman Mazumder, Rabi K Prusti, Smita MohantyAbstract:In moths, Pheromone-Binding Proteins (PBPs) are responsible for the transport of the hydrophobic Pheromones to the membrane-bound receptors across the aqueous sensillar lymph. We report here that recombinant Antheraea polyphemus PBP1 (ApolPBP1) picks up hydrophobic molecule(s) endogenous to the Escherichia coli expression host that keeps the Protein in the “open” (bound) conformation at high pH but switches to the “closed” (free) conformation at low pH. This finding has bearing on the solution structures of undelipidated lepidopteran moth PBPs determined thus far. Picking up a hydrophobic molecule from the host expression system could be a common feature for lipid-Binding Proteins. Thus, delipidation is critical for bacterially expressed lipid-Binding Proteins. We have shown for the first time that the delipidated ApolPBP1 exists primarily in the closed form at all pH levels. Thus, current views on the pH-induced conformational switch of PBPs hold true only for the ligand-bound open conformation of the Protein. Binding of various ligands to delipidated ApolPBP1 studied by solution NMR revealed that the Protein in the closed conformation switches to the open conformation only at or above pH 6.0 with a Protein to ligand stoichiometry of ∼1:1. Mutation of His70 and His95 to alanine drives the equilibrium toward the open conformation even at low pH for the ligand-bound Protein by eliminating the histidine-dependent pH-induced conformational switch. Thus, the delipidated double mutant can bind ligand even at low pH in contrast to the wild type Protein as revealed by fluorescence competitive displacement assay using 1-aminoanthracene and solution NMR.
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structural consequences of the ph induced conformational switch in a polyphemus Pheromone Binding Protein mechanisms of ligand release
Journal of Molecular Biology, 2005Co-Authors: Sergey Zubkov, Smita Mohanty, Angela M Gronenborn, Inja L ByeonAbstract:Olfaction in moths is one of the most impressive examples of chemical communication found in nature for its exquisite sensitivity and selectivity. Pheromone-Binding Proteins (PBPs), present in the antennae of male moth and other insect species, bind the hydrophobic Pheromone molecules and transport them to the G Protein-coupled olfactory receptor Proteins. The targeted delivery of these non-polar ligands to membrane-bound receptors involves ligand release on or near the target cell membranes, the molecular details of which are still not well understood. The PBP from the giant silk moth Antheraea polyphemus (ApolPBP) binds acetate Pheromone only at pH above 6.0, and its structure at pH 6.3 has been determined previously. Here we report the solution NMR structure of ApolPBP at the acidic pH 5.2. Comparison of the present structure to that at neutral pH reveals the details of the pH-induced conformational changes and provides mechanistic clues for ligand release at acidic pH. The ApolPBP pH-induced structural change is quite different from that observed for alcohol Binding Bombyx mori PBP (BmorPBP), where the C-terminal segment folds into a helix and occupies the ligand Binding cavity. We observe a reorientation of helices a1, a3, and a4 at acidic pH caused by protonation of His69, His70 and His95 in the interior. This provides the driving force behind the opening of the ligand Binding cavity and the release of the Pheromone molecule from its carrier Protein near the membrane.