View source for 1ib9


==SOLUTION STRUCTURE OF MCOTI-II, A MACROCYCLIC TRYPSIN INHIBITOR==
<StructureSection load='1ib9' size='340' side='right'caption='[[1ib9]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ib9]] 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=1IB9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1IB9 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 20 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=1ib9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ib9 OCA], [https://pdbe.org/1ib9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ib9 RCSB], [https://www.ebi.ac.uk/pdbsum/1ib9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ib9 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ITR2_MOMCO ITR2_MOMCO] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Much interest has been generated by recent reports on the discovery of circular (i.e. head-to-tail cyclized) proteins in plants. Here we report the three-dimensional structure of one of the newest such circular proteins, MCoTI-II, a novel trypsin inhibitor from Momordica cochinchinensis, a member of the Cucurbitaceae plant family. The structure consists of a small beta-sheet, several turns, and a cystine knot arrangement of the three disulfide bonds. Interestingly, the molecular topology is similar to that of the plant cyclotides (Craik, D. J., Daly, N. L., Bond, T., and Waine, C. (1999) J. Mol. Biol. 294, 1327-1336), which derive from the Rubiaceae and Violaceae plant families, have antimicrobial activities, and exemplify the cyclic cystine knot structural motif as part of their circular backbone. The sequence, biological activity, and plant family of MCoTI-II are all different from known cyclotides. However, given the structural similarity, cyclic backbone, and plant origin of MCoTI-II, we propose that MCoTI-II can be classified as a new member of the cyclotide class of proteins. The expansion of the cyclotides to include trypsin inhibitory activity and a new plant family highlights the importance and functional variability of circular proteins and the fact that they are more common than has previously been believed. Insights into the possible roles of backbone cyclization have been gained by a comparison of the structure of MCoTI-II with the homologous acyclic trypsin inhibitors CMTI-I and EETI-II from the Cucurbitaceae plant family.

Circular proteins in plants: solution structure of a novel macrocyclic trypsin inhibitor from Momordica cochinchinensis.,Felizmenio-Quimio ME, Daly NL, Craik DJ J Biol Chem. 2001 Jun 22;276(25):22875-82. Epub 2001 Apr 5. PMID:11292835<ref>PMID:11292835</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1ib9" 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: Craik DJ]]
[[Category: Daly NL]]
[[Category: Felizmenio-Quimio ME]]