2bhb: Difference between revisions

Revision as of 17:38, 21 February 2008

ZN SUBSTITUTED E. COLI AMINOPEPTIDASE P

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

2BHB is a Single protein structure of sequence from Escherichia coli with , , and as ligands. Active as Xaa-Pro aminopeptidase, with EC number 3.4.11.9 Known structural/functional Site: . 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

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 ==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.
+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==
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 [[Category: Single protein]]
 [[Category: Xaa-Pro aminopeptidase]]
-[[Category: Bond, C.S.]]
+[[Category: Bond, C S.]]
-[[Category: Freeman, H.C.]]
+[[Category: Freeman, H C.]]
-[[Category: Graham, S.C.]]
+[[Category: Graham, S C.]]
-[[Category: Guss, J.M.]]
+[[Category: Guss, J M.]]
 [[Category: FLC]]
 [[Category: MG]]
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 [[Category: proline-specific peptidase]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb  3 10:24:03 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:37:51 2008''