2bhc
From Proteopedia
(New page: 200px<br /><applet load="2bhc" size="450" color="white" frame="true" align="right" spinBox="true" caption="2bhc, resolution 2.40Å" /> '''NA SUBSTITUTED E. CO...) |
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| - | [[Image:2bhc.gif|left|200px]]<br /><applet load="2bhc" size=" | + | [[Image:2bhc.gif|left|200px]]<br /><applet load="2bhc" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2bhc, resolution 2.40Å" /> | caption="2bhc, resolution 2.40Å" /> | ||
'''NA SUBSTITUTED E. COLI AMINOPEPTIDASE P'''<br /> | '''NA SUBSTITUTED E. COLI AMINOPEPTIDASE P'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The effect of metal substitution on the activity and structure of the | + | 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== | ||
| - | 2BHC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with NA, FLC and MG 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] Full crystallographic information is available from [http:// | + | 2BHC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=NA:'>NA</scene>, <scene name='pdbligand=FLC:'>FLC</scene> and <scene name='pdbligand=MG:'>MG</scene> 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] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2BHC OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Xaa-Pro aminopeptidase]] | [[Category: Xaa-Pro aminopeptidase]] | ||
| - | [[Category: Bond, C | + | [[Category: Bond, C S.]] |
| - | [[Category: Freeman, H | + | [[Category: Freeman, H C.]] |
| - | [[Category: Graham, S | + | [[Category: Graham, S C.]] |
| - | [[Category: Guss, J | + | [[Category: Guss, J M.]] |
[[Category: FLC]] | [[Category: FLC]] | ||
[[Category: MG]] | [[Category: MG]] | ||
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[[Category: proline-specific peptidase]] | [[Category: proline-specific peptidase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:37:46 2008'' |
Revision as of 14:37, 21 February 2008
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NA SUBSTITUTED 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
2BHC 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 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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