1wo9
From Proteopedia
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| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1wo9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1wo9 OCA], [http://www.ebi.ac.uk/pdbsum/1wo9 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1wo9 RCSB]</span> | ||
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[[Category: hydrolase inhibitor]] | [[Category: hydrolase inhibitor]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 00:38:57 2008'' |
Revision as of 21:39, 30 March 2008
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Selective inhibition of trypsins by insect peptides: role of P6-P10 loop
Overview
PMP-D2 and HI, two peptides from Locusta migratoria, were shown to belong to the family of tight-binding protease inhibitors. However, they interact weakly with bovine trypsin (K(i) around 100 nM) despite a trypsin-specific Arg at the primary specificity site P1. Here we demonstrate that they are potent inhibitors of midgut trypsins isolated from the same insect and of a fungal trypsin from Fusarium oxysporum (K(i) <or= 0.02 nM). Therefore, they display a selectivity not existing for the parent chymotrypsin inhibitor PMP-C. By NMR, we demonstrate that HI possesses a highly rigid structure similar to the crystal structure of a variant of PMP-D2 in complex with bovine alpha-chymotrypsin. The main difference with PMP-C is located in the region from residues 20 to 24 (positions P6-P10) that interacts with the loop containing Gly173 in chymotrypsin. The corresponding residue in mammalian trypsins is always a proline that may generate a steric clash with the inhibitor. The residues thought to confer selectivity were mutated with PMP-C as a model. The resulting analogue PMP-D2(K10W,P21A,W25A) loses some activity toward insect and fungal trypsins but is a more potent inhibitor of mammalian trypsins, corresponding to a decrease of selectivity. This work represents a first attempt in tuning the selectivity of natural peptidic serine protease inhibitors by mutating residues out of the reactive loop (P3-P'3).
About this Structure
1WO9 is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Selective inhibition of trypsins by insect peptides: role of P6-P10 loop., Kellenberger C, Ferrat G, Leone P, Darbon H, Roussel A, Biochemistry. 2003 Nov 25;42(46):13605-12. PMID:14622007
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