The Experts below are selected from a list of 149652 Experts worldwide ranked by ideXlab platform
Neal J. Zondlo - One of the best experts on this subject based on the ideXlab platform.
-
design of a Protein Motif responsive to tyrosine nitration and an encoded turn off sensor of tyrosine nitration
Biochemistry, 2019Co-Authors: Andrew R Urmey, Neal J. ZondloAbstract:Tyrosine nitration is a Protein post-translational modification that is predominantly non-enzymatic and is observed to be increased under conditions of nitrosative stress and in numerous disease states. A small Protein Motif (14-18 amino acids) responsive to tyrosine nitration has been developed. In this design, nitrotyrosine replaced the conserved Glu12 of an EF-hand metal-binding Motif. Thus, the non-nitrated peptide bound terbium weakly. In contrast, tyrosine nitration resulted in a 45-fold increase in terbium affinity. Nuclear magnetic resonance spectroscopy indicated direct binding of nitrotyrosine to the metal and EF-hand-like metal contacts in this designed peptide. Nitrotyrosine is an efficient quencher of fluorescence. To develop a sensor of tyrosine nitration, the initial design was modified to incorporate Glu residues at EF-hand positions 9 and 16 as additional metal-binding residues, to increase the terbium affinity of the peptide with unmodified tyrosine. This peptide with a tyrosine at residue 12 bound terbium and effectively sensitized terbium luminescence. Tyrosine nitration resulted in a 180-fold increase in terbium affinity ( Kd = 1.6 μM) and quenching of terbium luminescence. This sequence was incorporated as an encoded Protein tag and applied as a turn-off fluorescent Protein sensor of tyrosine nitration. The sensor was responsive to nitration by peroxynitrite, with fluorescence quenched upon nitration. The greater terbium affinity upon tyrosine nitration resulted in a large dynamic range and sensitivity to substoichiometric nitration. An improved approach for the synthesis of peptides containing nitrotyrosine was also developed, via the in situ silyl protection of nitrotyrosine. This work represents the first designed, encodable Protein Motif that is responsive to tyrosine nitration.
-
Redox-Responsive Protein Design: Design of a Small Protein Motif Dependent on Glutathionylation
Biochemistry, 2018Co-Authors: Michael J. Scheuermann, Christina R. Forbes, Neal J. ZondloAbstract:Cysteine S-glutathionylation is a Protein post-translational modification that promotes cellular responses to changes in oxidative conditions. The design of Protein Motifs that directly depend on defined changes to Protein side chains provides new methods for probing diverse Protein post-translational modifications. A canonical, 12-residue EF-hand Motif was redesigned to be responsive to cysteine glutathionylation. The key design principle was the replacement of the metal-binding Glu12 carboxylate of an EF-hand with a Motif capable of metal binding via a free carboxylate in the glutathione-conjugated peptide. In the optimized peptide (DKDADGWCG), metal binding and terbium luminescence were dependent on glutathionylation, with weaker metal binding in the presence of reduced cysteine but increased metal affinity and a 3.5-fold increase in terbium luminescence at 544 nm when cysteine was glutathionylated. Nuclear magnetic resonance spectroscopy indicated that the structure at all residues of the glutathionylated peptide changed in the presence of metal, with chemical shift changes consistent with the adoption of an EF-hand-like structure in the metal-bound glutathionylated peptide. This small Protein Motif consists of canonical amino acids and is thus genetically encodable, for its potential use as a localized tag to probe Protein glutathionylation.
-
Design of an encodable tyrosine kinase-inducible domain: detection of tyrosine kinase activity by terbium luminescence.
Journal of the American Chemical Society, 2010Co-Authors: Susan Carr Zondlo, Feng Gao, Neal J. ZondloAbstract:Tyrosine kinases are critical mediators of intracellular signaling and of intracellular responses to extracellular signaling. Changes in tyrosine kinase activity are implicated in numerous human diseases, including cancers, diabetes, and pathogen infectivity. To address questions in tyrosine phosphorylation, we have designed a Protein tyrosine kinase-inducible domain, a small, genetically encodable Protein Motif whose structure is dependent on its tyrosine phosphorylation state. Tyrosine kinase-inducible domain peptides are based on EF-hand loops in which a structurally critical Glu12 residue is replaced by tyrosine at residue 11 or at residue 15 of the Protein. Tyrosine kinase-inducible domain peptides bind terbium(III) in a phosphorylation-dependent manner, showing strong terbium luminescence when phosphorylated but weak terbium luminescence when not phosphorylated. Lanthanide binding was confirmed by NMR. A tyrosine kinase-inducible domain peptide, pKID-Abl, was designed to incorporate a recognition se...
George N. Phillips - One of the best experts on this subject based on the ideXlab platform.
-
What is the pitch of the α‐helical coiled coil?
Proteins: Structure Function and Genetics, 1992Co-Authors: George N. PhillipsAbstract:The alpha-helical, coiled-coil Protein Motif is increasingly recognized in a variety of functional classes of Proteins. The pitch of a coiled coil, or rate of winding of the alpha-helices around each other, is a key determinant of both intra- and intermolecular interactions. Experimental measurements of the pitch of parallel two-stranded coiled coils of muscle Proteins, and examination of the recently determined structure of another two-stranded coiled coil, the GCN4 transcription factor Protein, suggest that the pitch has an average value of about 140 A. This value is consistent with the observed number of residues per turn in alpha-helices of globular Proteins, the determinant of the interhelical packing within the coiled-coil Motif. An understanding of the structural determinants of this value for the pitch and possible variations will be important in defining the interactions of coiled-coil Proteins with other macromolecules.
Robert Pola - One of the best experts on this subject based on the ideXlab platform.
-
The coiled coil Motif in polymer drug delivery systems.
Biotechnology Advances, 2013Co-Authors: Michal Pechar, Robert PolaAbstract:The coiled coil is a superhelical structural Protein Motif that has been thoroughly investigated in recent years. Because of the relatively well-understood principles that determine the properties of coiled coil peptides and Proteins, macromolecular systems containing the coiled coil Motif have been suggested for various applications. This short review focuses on hybrid polymer coiled coil systems designed for drug delivery purposes. After a short introduction, the most important features of the coiled coils (stability, association number, oligomerization selectivity and orientation of helices) are described, and the factors influencing these characteristics are discussed. Several examples of the most interesting biomedical applications of the polymer-coiled coil systems (according to the authors' opinion) are presented.
Silvia Corvera - One of the best experts on this subject based on the ideXlab platform.
-
Structural basis for endosomal targeting by FYVE domains.
The Journal of biological chemistry, 2003Co-Authors: Akira Hayakawa, Susan J. Hayes, Kevin E. Fogarty, David G. Lambright, Deirdre C Lawe, Eathiraj Sudharshan, Richard A. Tuft, Silvia CorveraAbstract:The FYVE domain is a conserved Protein Motif characterized by its ability to bind with high affinity and specificity to phosphatidylinositol 3-phosphate (PI3P), a phosphoinositide highly enriched in early endosomes. The PI3P polar head group contacts specific amino acid residues that are conserved among FYVE domains. Despite full conservation of these residues, the ability of different FYVE domains to bind to endosomes in cells is highly variable. Here we show that the endosomal localization in intact cells absolutely requires structural features intrinsic to the FYVE domain in addition to the PI3P binding pocket. These features are involved in FYVE domain dimerization and in interaction with the membrane bilayer. These interactions, which are determined by non-conserved residues, are likely to be essential for the temporal and spatial control of Protein associations at the membrane-cytosol interface within the endocytic pathway.
-
Signal transduction: stuck with FYVE domains.
Science's STKE : signal transduction knowledge environment, 2000Co-Authors: Silvia CorveraAbstract:The FYVE domain is a Protein Motif that allows the interaction of cytosolic Proteins with membranes containing the lipid phosphatidylinositol 3-phosphate. Structural information about FYVE domains has come from two crystal structures and NMR analysis. Corvera discusses how these structures differ and what they tell us about how Proteins with FYVE domains interact with biological membranes. The Perspective also addresses how Proteins with FYVE domains and Protein internalization are involved in signal transduction.
Andrew R Urmey - One of the best experts on this subject based on the ideXlab platform.
-
design of a Protein Motif responsive to tyrosine nitration and an encoded turn off sensor of tyrosine nitration
Biochemistry, 2019Co-Authors: Andrew R Urmey, Neal J. ZondloAbstract:Tyrosine nitration is a Protein post-translational modification that is predominantly non-enzymatic and is observed to be increased under conditions of nitrosative stress and in numerous disease states. A small Protein Motif (14-18 amino acids) responsive to tyrosine nitration has been developed. In this design, nitrotyrosine replaced the conserved Glu12 of an EF-hand metal-binding Motif. Thus, the non-nitrated peptide bound terbium weakly. In contrast, tyrosine nitration resulted in a 45-fold increase in terbium affinity. Nuclear magnetic resonance spectroscopy indicated direct binding of nitrotyrosine to the metal and EF-hand-like metal contacts in this designed peptide. Nitrotyrosine is an efficient quencher of fluorescence. To develop a sensor of tyrosine nitration, the initial design was modified to incorporate Glu residues at EF-hand positions 9 and 16 as additional metal-binding residues, to increase the terbium affinity of the peptide with unmodified tyrosine. This peptide with a tyrosine at residue 12 bound terbium and effectively sensitized terbium luminescence. Tyrosine nitration resulted in a 180-fold increase in terbium affinity ( Kd = 1.6 μM) and quenching of terbium luminescence. This sequence was incorporated as an encoded Protein tag and applied as a turn-off fluorescent Protein sensor of tyrosine nitration. The sensor was responsive to nitration by peroxynitrite, with fluorescence quenched upon nitration. The greater terbium affinity upon tyrosine nitration resulted in a large dynamic range and sensitivity to substoichiometric nitration. An improved approach for the synthesis of peptides containing nitrotyrosine was also developed, via the in situ silyl protection of nitrotyrosine. This work represents the first designed, encodable Protein Motif that is responsive to tyrosine nitration.
