1ast
From Proteopedia
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STRUCTURE OF ASTACIN AND IMPLICATIONS FOR ACTIVATION OF ASTACINS AND ZINC-LIGATION OF COLLAGENASES
Overview
Astacin, a digestive zinc-endopeptidase from the crayfish Astacus astacus, L., is the prototype for the 'astacin family', which includes mammalian, metallo-endopeptidases and developmentally regulated proteins of man, fruitfly, frog and sea urchin. Here we report the X-ray crystal structure, of astacin, which reveals a deep active-site cleft, with the zinc at its, bottom ligated by three histidines, a water molecule and a more remote, tyrosine. The third histidine (His 102) forms part of a consensus, sequence, shared not only by the members of the astacin family, but also, by otherwise sequentially unrelated proteinases, such as vertebrate, collagenases. It may therefore represent the elusive 'third' zinc ligand, in these enzymes. The amino terminus of astacin is buried forming an, internal salt-bridge with Glu 103, adjacent to His 102. Astacin pro-forms, extended at the N terminus, as observed for some 'latent' mammalian, astacin homologues, did not exhibit this 'active' conformation, indicating, an activation mechanism reminiscent of trypsin-like serine proteinases.
About this Structure
1AST is a Single protein structure of sequence from Astacus astacus with ZN as ligand. Active as Astacin, with EC number 3.4.24.21 Full crystallographic information is available from OCA.
Reference
Structure of astacin and implications for activation of astacins and zinc-ligation of collagenases., Bode W, Gomis-Ruth FX, Huber R, Zwilling R, Stocker W, Nature. 1992 Jul 9;358(6382):164-7. PMID:1319561
Page seeded by OCA on Tue Nov 20 11:06:42 2007
