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Rory R Duncan - One of the best experts on this subject based on the ideXlab platform.
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functionally and spatially distinct modes of munc18 syntaxin 1 interaction
Journal of Biological Chemistry, 2007Co-Authors: Colin Rickman, Claire N Medine, Axel Bergmann, Rory R DuncanAbstract:Eukaryotic membrane trafficking is a conserved process under tight temporal and spatial regulation in which the fusion of membranes is driven by the formation of the ternary SNARE complex. Syntaxin 1a, a core component of the exocytic SNARE1 complex in neurones and neuroendocrine cells, is regulated directly by munc18-1, its cognate Sm (Sec1p/Munc18) Protein. Sm Proteins show remarkable structural conservation throughout evolution indicating a common binding mechaniSm and function. However, Sm Proteins possess disparate binding mechaniSms and regulatory effects, with munc18-1, the major brain isoform, classed as atypical in both its binding specificity and mode. We now show that munc18-1 interacts with syntaxin 1a through two mechanistically distinct modes of binding, both in vitro and in living cells, in contrast to current models. Furthermore these functionally divergent interactions occur at distinct cellular locations. These findings provide a molecular explanation for the multiple, spatially distinct roles of munc18-1.
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functionally and spatially distinct modes of munc18 syntaxin 1 interaction
Journal of Biological Chemistry, 2007Co-Authors: Colin Rickman, Claire N Medine, Axel Bergmann, Rory R DuncanAbstract:Eukaryotic membrane trafficking is a conserved process under tight temporal and spatial regulation in which the fusion of membranes is driven by the formation of the ternary SNARE complex. Syntaxin 1a, a core component of the exocytic SNARE complex in neurons and neuroendocrine cells, is regulated directly by munc18-1, its cognate Sec1p/munc18 (Sm) Protein. Sm Proteins show remarkable structural conservation throughout evolution, indicating a common binding mechaniSm and function. However, Sm Proteins possess disparate binding mechaniSms and regulatory effects with munc18-1, the major brain isoform, classed as atypical in both its binding specificity and its mode. We now show that munc18-1 interacts with syntaxin 1a through two mechanistically distinct modes of binding, both in vitro and in living cells, in contrast to current models. Furthermore, these functionally divergent interactions occur at distinct cellular locations. These findings provide a molecular explanation for the multiple, spatially distinct roles of munc18-1.
Tatyana I. Odintsova - One of the best experts on this subject based on the ideXlab platform.
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Novel antifungal α-hairpinin peptide from Stellaria media seeds: structure, biosynthesis, gene structure and evolution
Plant Molecular Biology, 2013Co-Authors: Anna A. Slavokhotova, Eugene V. Grishin, Eugene A. Rogozhin, Tsezi A. Egorov, Yaroslav A. Andreev, Peter B. Oparin, Antonina A. Berkut, Alexander A. Vassilevski, Tatyana I. OdintsovaAbstract:Plant defense against disease is a complex multistage system involving initial recognition of the invading pathogen, signal transduction and activation of specialized genes. An important role in pathogen deterrence belongs to so-called plant defense peptides, Small polypeptide molecules that present antimicrobial properties. Using multidimensional liquid chromatography, we isolated a novel antifungal peptide named Sm-AMP-X (33 residues) from the common chickweed (Stellaria media) seeds. The peptide sequence shows no homology to any previously described Proteins. The peculiar cysteine arrangement (C1X3C2XnC3X3C4), however, allocates Sm-AMP-X to the recently acknowledged α-hairpinin family of plant defense peptides that share the helix-loop-helix fold stabilized by two disulfide bridges C1–C4 and C2–C3. Sm-AMP-X exhibits high broad-spectrum activity against fungal phytopathogens. We further showed that the N- and C-terminal “tail” regions of the peptide are important for both its structure and activity. The truncated variants Sm-AMP-X1 with both disulfide bonds preserved and Sm-AMP-X2 with only the internal S–S-bond left were progressively less active against fungi and presented largely disordered structure as opposed to the predominantly helical conformation of the full-length antifungal peptide. cDNA and gene cloning revealed that Sm-AMP-X is processed from a unique multimodular precursor Protein that contains as many as 12 tandem repeats of α-hairpinin-like peptides. Structure of the Sm-amp-x gene and two related pseudogenes Sm-amp-x-ψ1 and Sm-amp-x-ψ2 allows tracing the evolutionary scenario that led to generation of such a sophisticated precursor Protein. Sm-AMP-X is a new promising candidate for engineering disease resistance in plants.
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novel antifungal a hairpinin peptide from stellaria media seeds structure biosynthesis gene structure and evolution anna a slavokhotovaeugene a rogozhinalexander k musolyamov yaroslav a andreevpeter b oparinantonina a berkutalexander a vassilevski tsezi a egoroveugene v grishintatyana i odintsova
2013Co-Authors: Anna A. Slavokhotova, Tatyana I. Odintsova, Russian Federation, A V Andreev, A Vassilevski, V GrishinAbstract:Abstract Plant defense against disease is a complexmultistage system involving initial recognition of theinvading pathogen, signal transduction and activation ofspecialized genes. An important role in pathogen deter-rence belongs to so-called plant defense peptides, Smallpolypeptide molecules that present antimicrobial proper-ties. Using multidimensional liquid chromatography, weisolated a novel antifungal peptide named Sm-AMP-X (33residues) from the common chickweed (Stellaria media)seeds. The peptide sequence shows no homology to anypreviously described Proteins. The peculiar cysteinearrangement (C 1 X 3 C 2 X n C 3 X 3 C 4 ), however, allocates Sm-AMP-X to the recently acknowledged a-hairpinin family ofplant defense peptides that share the helix-loop-helix foldstabilized by two disulfide bridges C 1 –C 4 and C 2 –C 3 . Sm-AMP-X exhibits high broad-spectrum activity againstfungal phytopathogens. We further showed that the N- andC-terminal ‘‘tail’’ regions of the peptide are important forboth its structure and activity. The truncated variants Sm-AMP-X1 with both disulfide bonds preserved and Sm-AMP-X2 with only the internal S–S-bond left were pro-gressively less active against fungi and presented largelydisordered structure as opposed to the predominantlyhelical conformation of the full-length antifungal peptide.cDNA and gene cloning revealed that Sm-AMP-X is pro-cessed from a unique multimodular precursor Protein thatcontains as many as 12 tandem repeats of a-hairpinin-likepeptides. Structure of the Sm-amp-x gene and two relatedpseudogenes Sm-amp-x-w1 and Sm-amp-x-w2 allows trac-ing the evolutionary scenario that led to generation of sucha sophisticated precursor Protein. Sm-AMP-X is a newpromising candidate for engineering disease resistance inplants.Keywords Weeds cDNA cloning Gene structure Plant defense Protein biosynthesis a-hairpininIntroductionDuring evolution plants have developed a complex innateimmune system that protects them against microbialinvasion and pests. The defensive repertoire of plantsincludes both constitutive and inducible compounds acti-vated in response to pathogen attack or abiotic stress.Defense-related compounds involve phytoalexins andphytoanticipins, pathogenesis-related (PR) Proteins,enzyme inhibitors, and antimicrobial peptides (AMPs)(Selitrennikoff 2001; Sels et al. 2008; van Loon et al. 2006;Darvill 1984). AMPs are short polypeptides (molecular
R Lührmann - One of the best experts on this subject based on the ideXlab platform.
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Sm Protein-Sm site RNA interactions within the inner ring of the spliceosomal snRNP core structure.
The EMBO journal, 2001Co-Authors: H Urlaub, V A Raker, S Kostka, R LührmannAbstract:Seven Sm Proteins, E, F, G, D1, D2, D3 and B/B', assemble in a stepwise manner onto the single-stranded Sm site element (PuAU(4-6)GPu) of the U1, U2, U4 and U5 spliceosomal snRNAs, resulting in a doughnut-shaped core RNP structure. Here we show by UV cross-linking experiments using an Sm site RNA oligonucleotide (AAUUUUUGA) that several Sm Proteins contact the Sm site RNA, with the most efficient cross-links observed for the G and B/B' Proteins. Site-specific photo-cross-linking revealed that the G and B/B' Proteins contact distinct uridines (in the first and third positions, respectively) in a highly position-specific manner. Amino acids involved in contacting the RNA are located at equivalent regions in both Proteins, namely in loop L3 of the Sm1 motif, which has been predicted to jut into the hole of the Sm ring. Our results thus provide the first evidence that, within the core snRNP, multiple Sm Protein-Sm site RNA contacts occur on the inner surface of the heptameric Sm Protein ring.
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spliceosomal u snrnp core assembly Sm Proteins assemble onto an Sm site rna nonanucleotide in a specific and thermodynamically stable manner
Molecular and Cellular Biology, 1999Co-Authors: V A Raker, Klaus Hartmuth, Berthold Kastner, R LührmannAbstract:The association of Sm Proteins with U Small nuclear RNA (snRNA) requires the single-stranded Sm site (PuAU(4-6)GPu) but also is influenced by nonconserved flanking RNA structural elements. Here we demonstrate that a nonameric Sm site RNA oligonucleotide sufficed for sequence-specific assembly of a minimal core ribonucleoProtein (RNP), which contained all seven Sm Proteins. The minimal core RNP displayed several conserved biochemical features of native U snRNP core particles, including a similar morphology in electron micrographs. This minimal system allowed us to study in detail the RNA requirements for Sm Protein-Sm site interactions as well as the kinetics of core RNP assembly. In addition to the uridine bases, the 2' hydroxyl moieties were important for stable RNP formation, indicating that both the sugar backbone and the bases are intimately involved in RNA-Protein interactions. Moreover, our data imply that an initial phase of core RNP assembly is mediated by a high affinity of the Sm Proteins for the single-stranded uridine tract but that the presence of the conserved adenosine (PuAU.) is essential to commit the RNP particle to thermodynamic stability. Comparison of intact U4 and U5 snRNAs with the Sm site oligonucleotide in core RNP assembly revealed that the regions flanking the Sm site within the U snRNAs facilitate the kinetics of core RNP assembly by increasing the rate of Sm Protein association and by decreasing the activation energy.
Anna A. Slavokhotova - One of the best experts on this subject based on the ideXlab platform.
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Novel antifungal α-hairpinin peptide from Stellaria media seeds: structure, biosynthesis, gene structure and evolution
Plant Molecular Biology, 2013Co-Authors: Anna A. Slavokhotova, Eugene V. Grishin, Eugene A. Rogozhin, Tsezi A. Egorov, Yaroslav A. Andreev, Peter B. Oparin, Antonina A. Berkut, Alexander A. Vassilevski, Tatyana I. OdintsovaAbstract:Plant defense against disease is a complex multistage system involving initial recognition of the invading pathogen, signal transduction and activation of specialized genes. An important role in pathogen deterrence belongs to so-called plant defense peptides, Small polypeptide molecules that present antimicrobial properties. Using multidimensional liquid chromatography, we isolated a novel antifungal peptide named Sm-AMP-X (33 residues) from the common chickweed (Stellaria media) seeds. The peptide sequence shows no homology to any previously described Proteins. The peculiar cysteine arrangement (C1X3C2XnC3X3C4), however, allocates Sm-AMP-X to the recently acknowledged α-hairpinin family of plant defense peptides that share the helix-loop-helix fold stabilized by two disulfide bridges C1–C4 and C2–C3. Sm-AMP-X exhibits high broad-spectrum activity against fungal phytopathogens. We further showed that the N- and C-terminal “tail” regions of the peptide are important for both its structure and activity. The truncated variants Sm-AMP-X1 with both disulfide bonds preserved and Sm-AMP-X2 with only the internal S–S-bond left were progressively less active against fungi and presented largely disordered structure as opposed to the predominantly helical conformation of the full-length antifungal peptide. cDNA and gene cloning revealed that Sm-AMP-X is processed from a unique multimodular precursor Protein that contains as many as 12 tandem repeats of α-hairpinin-like peptides. Structure of the Sm-amp-x gene and two related pseudogenes Sm-amp-x-ψ1 and Sm-amp-x-ψ2 allows tracing the evolutionary scenario that led to generation of such a sophisticated precursor Protein. Sm-AMP-X is a new promising candidate for engineering disease resistance in plants.
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novel antifungal a hairpinin peptide from stellaria media seeds structure biosynthesis gene structure and evolution anna a slavokhotovaeugene a rogozhinalexander k musolyamov yaroslav a andreevpeter b oparinantonina a berkutalexander a vassilevski tsezi a egoroveugene v grishintatyana i odintsova
2013Co-Authors: Anna A. Slavokhotova, Tatyana I. Odintsova, Russian Federation, A V Andreev, A Vassilevski, V GrishinAbstract:Abstract Plant defense against disease is a complexmultistage system involving initial recognition of theinvading pathogen, signal transduction and activation ofspecialized genes. An important role in pathogen deter-rence belongs to so-called plant defense peptides, Smallpolypeptide molecules that present antimicrobial proper-ties. Using multidimensional liquid chromatography, weisolated a novel antifungal peptide named Sm-AMP-X (33residues) from the common chickweed (Stellaria media)seeds. The peptide sequence shows no homology to anypreviously described Proteins. The peculiar cysteinearrangement (C 1 X 3 C 2 X n C 3 X 3 C 4 ), however, allocates Sm-AMP-X to the recently acknowledged a-hairpinin family ofplant defense peptides that share the helix-loop-helix foldstabilized by two disulfide bridges C 1 –C 4 and C 2 –C 3 . Sm-AMP-X exhibits high broad-spectrum activity againstfungal phytopathogens. We further showed that the N- andC-terminal ‘‘tail’’ regions of the peptide are important forboth its structure and activity. The truncated variants Sm-AMP-X1 with both disulfide bonds preserved and Sm-AMP-X2 with only the internal S–S-bond left were pro-gressively less active against fungi and presented largelydisordered structure as opposed to the predominantlyhelical conformation of the full-length antifungal peptide.cDNA and gene cloning revealed that Sm-AMP-X is pro-cessed from a unique multimodular precursor Protein thatcontains as many as 12 tandem repeats of a-hairpinin-likepeptides. Structure of the Sm-amp-x gene and two relatedpseudogenes Sm-amp-x-w1 and Sm-amp-x-w2 allows trac-ing the evolutionary scenario that led to generation of sucha sophisticated precursor Protein. Sm-AMP-X is a newpromising candidate for engineering disease resistance inplants.Keywords Weeds cDNA cloning Gene structure Plant defense Protein biosynthesis a-hairpininIntroductionDuring evolution plants have developed a complex innateimmune system that protects them against microbialinvasion and pests. The defensive repertoire of plantsincludes both constitutive and inducible compounds acti-vated in response to pathogen attack or abiotic stress.Defense-related compounds involve phytoalexins andphytoanticipins, pathogenesis-related (PR) Proteins,enzyme inhibitors, and antimicrobial peptides (AMPs)(Selitrennikoff 2001; Sels et al. 2008; van Loon et al. 2006;Darvill 1984). AMPs are short polypeptides (molecular
Colin Rickman - One of the best experts on this subject based on the ideXlab platform.
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functionally and spatially distinct modes of munc18 syntaxin 1 interaction
Journal of Biological Chemistry, 2007Co-Authors: Colin Rickman, Claire N Medine, Axel Bergmann, Rory R DuncanAbstract:Eukaryotic membrane trafficking is a conserved process under tight temporal and spatial regulation in which the fusion of membranes is driven by the formation of the ternary SNARE complex. Syntaxin 1a, a core component of the exocytic SNARE1 complex in neurones and neuroendocrine cells, is regulated directly by munc18-1, its cognate Sm (Sec1p/Munc18) Protein. Sm Proteins show remarkable structural conservation throughout evolution indicating a common binding mechaniSm and function. However, Sm Proteins possess disparate binding mechaniSms and regulatory effects, with munc18-1, the major brain isoform, classed as atypical in both its binding specificity and mode. We now show that munc18-1 interacts with syntaxin 1a through two mechanistically distinct modes of binding, both in vitro and in living cells, in contrast to current models. Furthermore these functionally divergent interactions occur at distinct cellular locations. These findings provide a molecular explanation for the multiple, spatially distinct roles of munc18-1.
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functionally and spatially distinct modes of munc18 syntaxin 1 interaction
Journal of Biological Chemistry, 2007Co-Authors: Colin Rickman, Claire N Medine, Axel Bergmann, Rory R DuncanAbstract:Eukaryotic membrane trafficking is a conserved process under tight temporal and spatial regulation in which the fusion of membranes is driven by the formation of the ternary SNARE complex. Syntaxin 1a, a core component of the exocytic SNARE complex in neurons and neuroendocrine cells, is regulated directly by munc18-1, its cognate Sec1p/munc18 (Sm) Protein. Sm Proteins show remarkable structural conservation throughout evolution, indicating a common binding mechaniSm and function. However, Sm Proteins possess disparate binding mechaniSms and regulatory effects with munc18-1, the major brain isoform, classed as atypical in both its binding specificity and its mode. We now show that munc18-1 interacts with syntaxin 1a through two mechanistically distinct modes of binding, both in vitro and in living cells, in contrast to current models. Furthermore, these functionally divergent interactions occur at distinct cellular locations. These findings provide a molecular explanation for the multiple, spatially distinct roles of munc18-1.
