1w2m
From Proteopedia
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[[Category: proline-specific peptidase]] | [[Category: proline-specific peptidase]] | ||
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Revision as of 15:18, 5 November 2007
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CA-SUBSTITUTED FORM OF E. COLI AMINOPEPTIDASE P
Overview
The effect of metal substitution on the activity and structure of the, aminopeptidase P (APPro) from Escherichia coli has been investigated., Measurements of activity in the presence of Mn2+, Mg2+, Zn2+, Na+, and, Ca2+ show that significant activity is seen only in the Mn-bound form of, the enzyme. The addition of Zn2+ to [MnMn(APPro)] is strongly inhibitory., Crystal structures of [MnMn(APPro)], [MgMg(APPro)], [ZnZn(APPro)], [ZnMg(APPro)], [Ca_(APPro)], [Na_(APPro)], and [apo(APPro)] were, determined. The structures of [Ca_(APPro)] and [Na_(APPro)] have a single, metal atom at their active site. Surprisingly, when a tripeptide substrate, (ValProLeu) was soaked into [Na_(APPro)] crystals in the presence of 200, mM Mg2+, the structure had substrate, but no metal, bound at the active, site. The structure of apo APPro complexed with ValProLeu shows that the, N-terminal amino group of a substrate can be bound at the active site by, carboxylate side chains that normally bind the second metal atom, providing a model for substrate binding in a single-metal active enzyme., Structures of [MnMn(APPro)] and [ZnZn(APPro)] complexes of ProLeu, a, product inhibitor, in the presence of excess Zn reveal a third, metal-binding site, formed by two conserved His residues and the dipeptide, inhibitor. A Zn atom bound at such a site would stabilize product binding, and enhance inhibition.
About this Structure
1W2M is a Single protein structure of sequence from Escherichia coli with CA, CL and IPA as ligands. Active as Xaa-Pro aminopeptidase, with EC number 3.4.11.9 Structure known Active Site: AC1. Full crystallographic information is available from OCA.
Reference
Structural and functional implications of metal ion selection in aminopeptidase P, a metalloprotease with a dinuclear metal center., Graham SC, Bond CS, Freeman HC, Guss JM, Biochemistry. 2005 Oct 25;44(42):13820-36. PMID:16229471
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