1sek
From Proteopedia
THE STRUCTURE OF ACTIVE SERPIN K FROM MANDUCA SEXTA AND A MODEL FOR SERPIN-PROTEASE COMPLEX FORMATION
Overview
BACKGROUND: The reactive center loops (RCL) of serpins undergo large conformational changes triggered by the interaction with their target protease. Available crystallographic data suggest that the serpin RCL is polymorphic, but the relevance of the observed conformations to the competent active structure and the conformational changes that occur on binding target protease has remained obscure. New high-resolution data on an active serpin, serpin 1K from the moth hornworm Manduca sexta, provide insights into how active serpins are stabilized and how conformational changes are induced by protease binding. RESULTS: The 2.1 A structure shows that the RCL of serpin 1K, like that of active alpha1-antitrypsin, is canonical, complimentary and ready to bind to the target protease between P3 and P3 (where P refers to standard protease nomenclature),. In the hinge region (P17-P13), however, the RCL of serpin 1K, like ovalbumin and alpha1-antichymotrypsin, forms tight interactions that stabilize the five-stranded closed form of betasheet A. These interactions are not present in, and are not compatible with, the observed structure of active alpha1-antitrypsin. CONCLUSIONS: Serpin 1K may represent the best resting conformation for serpins - canonical near P1, but stabilized in the closed conformation of betasheet A. By comparison with other active serpins, especially alpha1-antitrypsin, a model is proposed in which interaction with the target protease near P1 leads to conformational changes in betasheet A of the serpin.
About this Structure
1SEK is a Single protein structure of sequence from Manduca sexta. Full crystallographic information is available from OCA.
Reference
The structure of active serpin 1K from Manduca sexta., Li J, Wang Z, Canagarajah B, Jiang H, Kanost M, Goldsmith EJ, Structure. 1999 Jan 15;7(1):103-9. PMID:10368276 Page seeded by OCA on Sat May 3 08:36:36 2008
