2bn7: Difference between revisions
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'''MN SUBSTITUTED E. COLI AMINOPEPTIDASE P IN COMPLEX WITH PRODUCT AND ZN''' | '''MN SUBSTITUTED E. COLI AMINOPEPTIDASE P IN COMPLEX WITH PRODUCT AND ZN''' | ||
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[[Category: Graham, S C.]] | [[Category: Graham, S C.]] | ||
[[Category: Guss, J M.]] | [[Category: Guss, J M.]] | ||
[[Category: | [[Category: Dinuclear hydrolase]] | ||
[[Category: | [[Category: Metalloenzyme]] | ||
[[Category: | [[Category: Pita-bread fold]] | ||
[[Category: | [[Category: Product complex]] | ||
[[Category: | [[Category: Proline-specific peptidase]] | ||
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Revision as of 20:31, 3 May 2008
MN SUBSTITUTED E. COLI AMINOPEPTIDASE P IN COMPLEX WITH PRODUCT AND ZN
OverviewOverview
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 StructureAbout this Structure
2BN7 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
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 20:31:26 2008