2bhd: Difference between revisions
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==Overview== | ==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 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== | ==About this Structure== | ||
2BHD is a | 2BHD is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with MG and FLC as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Xaa-Pro_aminopeptidase Xaa-Pro aminopeptidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.11.9 3.4.11.9] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BHD OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: proline-specific peptidase]] | [[Category: proline-specific peptidase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 13:55:26 2007'' | ||
