8gch
From Proteopedia
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GAMMA-CHYMOTRYPSIN IS A COMPLEX OF ALPHA-CHYMOTRYPSIN WITH ITS OWN AUTOLYSIS PRODUCTS
Overview
The determination of three separate gamma-chymotrypsin structures at, different temperatures and resolutions confirmed the presence of electron, density in the active site, which could be interpreted as an oligopeptide, as had previously been suggested by Dixon and Matthews [(1989), Biochemistry 28, 7033-7038]. HPLC analyses of the enzyme before and after, crystallization demonstrated the presence of a wide variety of, oligopeptides in the redissolved crystal, most with COOH-terminal aromatic, residues, as expected of the products of chymotrypsin cleavage, which, appeared to arise from extensive autolysis of the enzyme under the, crystallization conditions. The refined structures agree well with the, conformation of both gamma-chymotrypsin and alpha-chymotrypsin. The, electron density in the active site is thus interpreted as arising from a, repertoire of autolysed oligopeptides produced concomitantly with, crystallization. The COOH-terminal carbons of the polypeptide(s) display, short contact distances (1.97, 2.47, and 2.13 A, respectively) to Ser195 O, gamma in all three refined structures, but the electron density is not, continuous between these two atoms in any of them. This suggests that some, sequences are covalently bound as enzyme intermediates while others are, noncovalently bound as enzyme-product complexes.
About this Structure
8GCH is a Protein complex structure of sequences from Bos taurus with SO4 as ligand. Active as Chymotrypsin, with EC number 3.4.21.1 Full crystallographic information is available from OCA.
Reference
Gamma-chymotrypsin is a complex of alpha-chymotrypsin with its own autolysis products., Harel M, Su CT, Frolow F, Silman I, Sussman JL, Biochemistry. 1991 May 28;30(21):5217-25. PMID:2036388
Page seeded by OCA on Thu Nov 8 12:55:20 2007
