This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1wl6
From Proteopedia
(New page: 200px<br /><applet load="1wl6" size="450" color="white" frame="true" align="right" spinBox="true" caption="1wl6, resolution 2.00Å" /> '''Mg-substituted form ...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1wl6.jpg|left|200px]]<br /><applet load="1wl6" size=" | + | [[Image:1wl6.jpg|left|200px]]<br /><applet load="1wl6" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1wl6, resolution 2.00Å" /> | caption="1wl6, resolution 2.00Å" /> | ||
'''Mg-substituted form of E. coli aminopeptidase P'''<br /> | '''Mg-substituted form of 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== | ||
| - | 1WL6 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 MG, CL, XPE and IPA 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:// | + | 1WL6 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=MG:'>MG</scene>, <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=XPE:'>XPE</scene> and <scene name='pdbligand=IPA:'>IPA</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=1WL6 OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[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: CL]] | [[Category: CL]] | ||
[[Category: IPA]] | [[Category: IPA]] | ||
| Line 26: | Line 26: | ||
[[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 15:45:32 2008'' |
Revision as of 13:45, 21 February 2008
|
Mg-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
1WL6 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
Page seeded by OCA on Thu Feb 21 15:45:32 2008
