1w2m
From Proteopedia
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'''CA-SUBSTITUTED FORM OF E. COLI AMINOPEPTIDASE P''' | '''CA-SUBSTITUTED FORM OF E. COLI AMINOPEPTIDASE P''' | ||
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[[Category: Graham, S C.]] | [[Category: Graham, S C.]] | ||
[[Category: Guss, J M.]] | [[Category: Guss, J M.]] | ||
| - | [[Category: | + | [[Category: Aminopeptidase]] |
| - | [[Category: | + | [[Category: Metalloenzyme]] |
| - | [[Category: | + | [[Category: Metalloprotease]] |
| - | [[Category: | + | [[Category: Pita-bread fold]] |
| - | [[Category: | + | [[Category: Proline-specific peptidase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 13:03:59 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 10:04, 3 May 2008
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. 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 Page seeded by OCA on Sat May 3 13:03:59 2008
