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| - | [[Image:1o8z.jpg|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1o8z| PDB=1o8z | SCENE= }} | | {{STRUCTURE_1o8z| PDB=1o8z | SCENE= }} |
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| - | '''SOLUTION STRUCTURE OF SFTI-1(6,5), AN ACYCLIC PERMUTANT OF THE PROTEINASE INHIBITOR SFTI-1, CIS-TRANS-TRANS CONFORMER (CT-A)'''
| + | ===SOLUTION STRUCTURE OF SFTI-1(6,5), AN ACYCLIC PERMUTANT OF THE PROTEINASE INHIBITOR SFTI-1, CIS-TRANS-TRANS CONFORMER (CT-A)=== |
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| - | ==Overview==
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| - | The most potent known naturally occurring Bowman-Birk inhibitor, sunflower trypsin inhibitor-1 (SFTI-1), is a bicyclic 14-amino acid peptide from sunflower seeds comprising one disulfide bond and a cyclic backbone. At present, little is known about the cyclization mechanism of SFTI-1. We show here that an acyclic permutant of SFTI-1 open at its scissile bond, SFTI-1[6,5], also functions as an inhibitor of trypsin and that it can be enzymatically backbone-cyclized by incubation with bovine beta-trypsin. The resulting ratio of cyclic SFTI-1 to SFTI-1[6,5] is approximately 9:1 regardless of whether trypsin is incubated with SFTI-1[6,5] or SFTI-1. Enzymatic resynthesis of the scissile bond to form cyclic SFTI-1 is a novel mechanism of cyclization of SFTI-1[6,5]. Such a reaction could potentially occur on a trypsin affinity column as used in the original isolation procedure of SFTI-1. We therefore extracted SFTI-1 from sunflower seeds without a trypsin purification step and confirmed that the backbone of SFTI-1 is indeed naturally cyclic. Structural studies on SFTI-1[6,5] revealed high heterogeneity, and multiple species of SFTI-1[6,5] were identified. The main species closely resembles the structure of cyclic SFTI-1 with the broken binding loop able to rotate between a cis/trans geometry of the I7-P8 bond with the cis conformer being similar to the canonical binding loop conformation. The non-reactive loop adopts a beta-hairpin structure as in cyclic wild-type SFTI-1. Another species exhibits an iso-aspartate residue at position 14 and provides implications for possible in vivo cyclization mechanisms. | + | The line below this paragraph, {{ABSTRACT_PUBMED_12621047}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 12621047 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_12621047}} |
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| | ==About this Structure== | | ==About this Structure== |
| - | 1O8Z is a [[Single protein]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1O8Z OCA]. | + | 1O8Z is a [[Single protein]] structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1O8Z OCA]. |
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| | ==Reference== | | ==Reference== |
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| | [[Category: Bowman-birk inhibitor]] | | [[Category: Bowman-birk inhibitor]] |
| | [[Category: Sfti-1]] | | [[Category: Sfti-1]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 03:32:17 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat Jul 5 16:18:19 2008'' |
Revision as of 13:18, 5 July 2008
Template:STRUCTURE 1o8z
SOLUTION STRUCTURE OF SFTI-1(6,5), AN ACYCLIC PERMUTANT OF THE PROTEINASE INHIBITOR SFTI-1, CIS-TRANS-TRANS CONFORMER (CT-A)
Template:ABSTRACT PUBMED 12621047
About this Structure
1O8Z is a Single protein structure. Full experimental information is available from OCA.
Reference
Enzymatic cyclization of a potent bowman-birk protease inhibitor, sunflower trypsin inhibitor-1, and solution structure of an acyclic precursor peptide., Marx UC, Korsinczky ML, Schirra HJ, Jones A, Condie B, Otvos L Jr, Craik DJ, J Biol Chem. 2003 Jun 13;278(24):21782-9. Epub 2003 Mar 5. PMID:12621047
Page seeded by OCA on Sat Jul 5 16:18:19 2008
