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==SOLUTION STRUCTURE OF THE SQUASH TRYPSIN INHIBITOR MCoTI-II, NMR, 30 STRUCTURES.== | |||
<StructureSection load='1ha9' size='340' side='right'caption='[[1ha9]]' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1ha9]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Momordica_cochinchinensis Momordica cochinchinensis]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HA9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1HA9 FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 30 models</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PRD_000750:CYCLIC+KNOTTIN+TRYPSIN+INHIBITOR+II'>PRD_000750</scene></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1ha9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ha9 OCA], [https://pdbe.org/1ha9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ha9 RCSB], [https://www.ebi.ac.uk/pdbsum/1ha9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ha9 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/ITR2_MOMCO ITR2_MOMCO] | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The "knottin" fold is a stable cysteine-rich scaffold, in which one disulfide crosses the macrocycle made by two other disulfides and the connecting backbone segments. This scaffold is found in several protein families with no evolutionary relationships. In the past few years, several homologous peptides from the Rubiaceae and Violaceae families were shown to define a new structural family based on macrocyclic knottin fold. We recently isolated from Momordica cochinchinensis seeds the first known macrocyclic squash trypsin inhibitors. These compounds are the first members of a new family of cyclic knottins. In this paper, we present NMR structural studies of one of them, MCoTI-II, and of a beta-Asp rearranged form, MCoTI-IIb. Both compounds display similar and well-defined conformations. These cyclic squash inhibitors share a similar conformation with noncyclic squash inhibitors such as CPTI-II, and it is postulated that the main effect of the cyclization is a reduced sensitivity to exo-proteases. On the contrary, clear differences were detected with the three-dimensional structures of other known cyclic knottins, i.e., kalata B1 or circulin A. The two-disulfide cystine-stabilized beta-sheet motif [Heitz et al. (1999) Biochemistry 38, 10615-10625] is conserved in the two families, whereas in the C-to-N linker, one disulfide bridge and one loop are differently located. The molecular surface of MCoTI-II is almost entirely charged in contrast to circulin A that displays a well-marked amphiphilic character. These differences might explain why the isolated macrocyclic squash inhibitors from M. cochinchinensis display no significant antibacterial activity, whereas circulins and kalata B1 do. | |||
Solution structure of the squash trypsin inhibitor MCoTI-II. A new family for cyclic knottins.,Heitz A, Hernandez JF, Gagnon J, Hong TT, Pham TT, Nguyen TM, Le-Nguyen D, Chiche L Biochemistry. 2001 Jul 10;40(27):7973-83. PMID:11434766<ref>PMID:11434766</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1ha9" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Trypsin inhibitor 3D structures|Trypsin inhibitor 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Large Structures]] | |||
[[Category: Momordica cochinchinensis]] | [[Category: Momordica cochinchinensis]] | ||
[[Category: Chiche L]] | |||
[[Category: Chiche | [[Category: Gagnon J]] | ||
[[Category: Gagnon | [[Category: Heitz A]] | ||
[[Category: Heitz | [[Category: Hernandez J-F]] | ||
[[Category: Hernandez | [[Category: Hong TT]] | ||
[[Category: Hong | [[Category: Le-Nguyen D]] | ||
[[Category: Le-Nguyen | [[Category: Nguyen TM]] | ||
[[Category: Nguyen | [[Category: Pham TTC]] | ||
[[Category: Pham | |||
Latest revision as of 07:34, 17 October 2024
SOLUTION STRUCTURE OF THE SQUASH TRYPSIN INHIBITOR MCoTI-II, NMR, 30 STRUCTURES.SOLUTION STRUCTURE OF THE SQUASH TRYPSIN INHIBITOR MCoTI-II, NMR, 30 STRUCTURES.
Structural highlights
FunctionPublication Abstract from PubMedThe "knottin" fold is a stable cysteine-rich scaffold, in which one disulfide crosses the macrocycle made by two other disulfides and the connecting backbone segments. This scaffold is found in several protein families with no evolutionary relationships. In the past few years, several homologous peptides from the Rubiaceae and Violaceae families were shown to define a new structural family based on macrocyclic knottin fold. We recently isolated from Momordica cochinchinensis seeds the first known macrocyclic squash trypsin inhibitors. These compounds are the first members of a new family of cyclic knottins. In this paper, we present NMR structural studies of one of them, MCoTI-II, and of a beta-Asp rearranged form, MCoTI-IIb. Both compounds display similar and well-defined conformations. These cyclic squash inhibitors share a similar conformation with noncyclic squash inhibitors such as CPTI-II, and it is postulated that the main effect of the cyclization is a reduced sensitivity to exo-proteases. On the contrary, clear differences were detected with the three-dimensional structures of other known cyclic knottins, i.e., kalata B1 or circulin A. The two-disulfide cystine-stabilized beta-sheet motif [Heitz et al. (1999) Biochemistry 38, 10615-10625] is conserved in the two families, whereas in the C-to-N linker, one disulfide bridge and one loop are differently located. The molecular surface of MCoTI-II is almost entirely charged in contrast to circulin A that displays a well-marked amphiphilic character. These differences might explain why the isolated macrocyclic squash inhibitors from M. cochinchinensis display no significant antibacterial activity, whereas circulins and kalata B1 do. Solution structure of the squash trypsin inhibitor MCoTI-II. A new family for cyclic knottins.,Heitz A, Hernandez JF, Gagnon J, Hong TT, Pham TT, Nguyen TM, Le-Nguyen D, Chiche L Biochemistry. 2001 Jul 10;40(27):7973-83. PMID:11434766[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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