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8pch
From Proteopedia
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[[Category: protease]] | [[Category: protease]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 18:51:26 2007'' |
Revision as of 16:46, 5 November 2007
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CRYSTAL STRUCTURE OF PORCINE CATHEPSIN H DETERMINED AT 2.1 ANGSTROM RESOLUTION: LOCATION OF THE MINI-CHAIN C-TERMINAL CARBOXYL GROUP DEFINES CATHEPSIN H AMINOPEPTIDASE FUNCTION
Overview
BACKGROUND: Cathepsin H is a lysosomal cysteine protease, involved in, intracellular protein degradation. It is the only known, mono-aminopeptidase in the papain-like family and is reported to be, involved in tumor metastasis. The cathepsin H structure was determined in, order to investigate the structural basis for its aminopeptidase activity, and thus to provide the basis for structure-based design of synthetic, inhibitors. RESULTS: The crystal structure of native porcine cathepsin H, was determined at 2.1 A resolution. The structure has the typical, papain-family fold. The so-called mini-chain, the octapeptide EPQNCSAT, is, attached via a disulfide bond to the body of the enzyme and bound in a, narrowed active-site cleft, in the substrate-binding direction. The, mini-chain fills the region that in related enzymes comprises the, non-primed substrate-binding sites from S2 backwards. CONCLUSIONS: The, crystal structure of cathepsin H reveals that the mini-chain has a, definitive role in substrate recognition and that carbohydrate residues, attached to the body of the enzyme are involved in positioning the, mini-chain in the active-site cleft. Modeling of a substrate into the, active-site cleft suggests that the negatively charged carboxyl group of, the C terminus of the mini-chain acts as an anchor for the positively, charged N-terminal amino group of a substrate. The observed displacements, of the residues within the active-site cleft from their equivalent, positions in the papain-like endopeptidases suggest that they form the, structural basis for the positioning of both the mini-chain and the, substrate, resulting in exopeptidase activity.
About this Structure
8PCH is a Single protein structure of sequence from Sus scrofa. Active as Cathepsin H, with EC number 3.4.22.16 Structure known Active Site: ACT. Full crystallographic information is available from OCA.
Reference
Crystal structure of porcine cathepsin H determined at 2.1 A resolution: location of the mini-chain C-terminal carboxyl group defines cathepsin H aminopeptidase function., Guncar G, Podobnik M, Pungercar J, Strukelj B, Turk V, Turk D, Structure. 1998 Jan 15;6(1):51-61. PMID:9493267
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