CRYSTAL STRUCTURE OF MICHAELIS SERPIN-TRYPSIN COMPLEX

File:1k9o.jpg


PDB ID 1k9o

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, resolution 2.3Å
Activity: Trypsin, with EC number 3.4.21.4
Coordinates: save as pdb, mmCIF, xml



OverviewOverview

Serine protease inhibitors (serpins) regulate the activities of circulating proteases. Serpins inhibit proteases by acylating the serine hydroxyl at their active sites. Before deacylation and complete proteolysis of the serpin can occur, massive conformational changes are triggered in the serpin while maintaining the covalent linkage between the protease and serpin. Here we report the structure of a serpin-trypsin Michaelis complex, which we visualized by using the S195A trypsin mutant to prevent covalent complex formation. This encounter complex reveals a more extensive interaction surface than that present in small inhibitor-protease complexes and is a template for modeling other serpin-protease pairs. Mutations of several serpin residues at the interface reduced the inhibitory activity of the serpin. The serine residue C-terminal to the scissile peptide bond is found in a closer than usual interaction with His 57 at the active site of trypsin.

About this StructureAbout this Structure

1K9O is a Protein complex structure of sequences from Manduca sexta and Rattus norvegicus. This structure supersedes the now removed PDB entry 1I99. The following page contains interesting information on the relation of 1K9O with [Serpins]. Full crystallographic information is available from OCA.

ReferenceReference

The structure of a Michaelis serpin-protease complex., Ye S, Cech AL, Belmares R, Bergstrom RC, Tong Y, Corey DR, Kanost MR, Goldsmith EJ, Nat Struct Biol. 2001 Nov;8(11):979-83. PMID:11685246

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