View source for 1jbn


==Solution structure of an acyclic permutant of SFTI-1, A trypsin inhibitor from sunflower seeds==
<StructureSection load='1jbn' size='340' side='right'caption='[[1jbn]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1jbn]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Helianthus_annuus Helianthus annuus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JBN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1JBN 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='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1jbn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jbn OCA], [https://pdbe.org/1jbn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1jbn RCSB], [https://www.ebi.ac.uk/pdbsum/1jbn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1jbn ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SFTI1_HELAN SFTI1_HELAN] Inhibits trypsin, cathepsin G, elastase, chymotrypsin and thrombin. Does not inhibit factor Xa.<ref>PMID:10390350</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
SFTI-1 is a recently discovered cyclic peptide trypsin inhibitor from sunflower seeds comprising 14 amino acid residues. It is the most potent known Bowman-Birk inhibitor and the only naturally occurring cyclic one. The solution structure of SFTI-1 has been determined by 1H-NMR spectroscopy and compared with a synthetic acyclic permutant. The solution structures of both are remarkably similar. The lowest energy structures from each family of 20 structures of cyclic and acyclic SFTI-1 have an rmsd over the backbone and heavy atoms of 0.29 A and 0.66 A, respectively. The structures consist of two short antiparallel beta-strands joined by an extended loop containing the active site at one end. Cyclic SFTI-1 also has a hairpin turn completing the cycle. Both molecules contain particularly stable arrangements of cross-linking hydrogen bonds between the beta-strands and a single disulfide bridge, making them rigid and well defined in solution. These stable arrangements allow both the cyclic and acyclic variants of SFTI-1 to inhibit trypsin with very high potencies (0.5 nM and 12.1 nM, respectively). The cyclic nature of SFTI-1 appears to have evolved to provide higher trypsin inhibition as well as higher stability. The solution structures are similar to the crystal structure of the cyclic inhibitor in complex with trypsin. The lack of a major conformational change upon binding suggests that the structure of SFTI-1 is rigid and already pre-organized for maximal binding due to minimization of entropic losses compared to a more flexible ligand. These properties make SFTI-1 an ideal platform for the design of small peptidic pharmaceuticals or pesticides.

Solution structures by 1H NMR of the novel cyclic trypsin inhibitor SFTI-1 from sunflower seeds and an acyclic permutant.,Korsinczky ML, Schirra HJ, Rosengren KJ, West J, Condie BA, Otvos L, Anderson MA, Craik DJ J Mol Biol. 2001 Aug 17;311(3):579-91. PMID:11493011<ref>PMID:11493011</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1jbn" style="background-color:#fffaf0;"></div>

==See Also==
*[[Trypsin inhibitor 3D structures|Trypsin inhibitor 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Helianthus annuus]]
[[Category: Large Structures]]
[[Category: Anderson MA]]
[[Category: Condie BA]]
[[Category: Craik DJ]]
[[Category: Korsinczky MLJ]]
[[Category: Otvos L]]
[[Category: Rosengren KJ]]
[[Category: Schirra HJ]]
[[Category: West J]]