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
8pch is a 2 chain structure with sequence from Sus scrofa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
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.
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[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑Guncar G, Podobnik M, Pungercar J, Strukelj B, Turk V, Turk D. 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. Structure. 1998 Jan 15;6(1):51-61. PMID:9493267