1y7a
From Proteopedia
(New page: 200px<br /><applet load="1y7a" size="450" color="white" frame="true" align="right" spinBox="true" caption="1y7a, resolution 1.77Å" /> '''Structure of D153H/K...) |
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| - | [[Image:1y7a.gif|left|200px]]<br /><applet load="1y7a" size=" | + | [[Image:1y7a.gif|left|200px]]<br /><applet load="1y7a" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1y7a, resolution 1.77Å" /> | caption="1y7a, resolution 1.77Å" /> | ||
'''Structure of D153H/K328W E. coli alkaline phosphatase in presence of cobalt at 1.77 A resolution'''<br /> | '''Structure of D153H/K328W E. coli alkaline phosphatase in presence of cobalt at 1.77 A resolution'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Escherichia coli alkaline phosphatase exhibits maximal activity when | + | Escherichia coli alkaline phosphatase exhibits maximal activity when Zn(2+) fills the M1 and M2 metal sites and Mg(2+) fills the M3 metal site. When other metals replace the zinc and magnesium, the catalytic efficiency is reduced by more than 5000-fold. Alkaline phosphatases from organisms such as Thermotoga maritima and Bacillus subtilis require cobalt for maximal activity and function poorly with zinc and magnesium. Previous studies have shown that the D153H alkaline phosphatase exhibited very little activity in the presence of cobalt, while the K328W and especially the D153H/K328W mutant enzymes can use cobalt for catalysis. To understand the structural basis for the altered metal specificity and the ability of the D153H/K328W enzyme to utilize cobalt for catalysis, we determined the structures of the inactive wild-type E. coli enzyme with cobalt (WT_Co) and the structure of the active D153H/K328W enzyme with cobalt (HW_Co). The structural data reveal differences in the metal coordination and in the strength of the interaction with the product phosphate (P(i)). Since release of P(i) is the slow step in the mechanism at alkaline pH, the enhanced binding of P(i) in the WT_Co structure explains the observed decrease in activity, while the weakened binding of P(i) in the HW_Co structure explains the observed increase in activity. These alterations in P(i) affinity are directly related to alterations in the coordination of the metals in the active site of the enzyme. |
==About this Structure== | ==About this Structure== | ||
| - | 1Y7A 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 CO, PO4 and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alkaline_phosphatase Alkaline phosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.1 3.1.3.1] Full crystallographic information is available from [http:// | + | 1Y7A 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=CO:'>CO</scene>, <scene name='pdbligand=PO4:'>PO4</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alkaline_phosphatase Alkaline phosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.1 3.1.3.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Y7A OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Kantrowitz, E | + | [[Category: Kantrowitz, E R.]] |
[[Category: Stieglitz, K.]] | [[Category: Stieglitz, K.]] | ||
[[Category: Wang, J.]] | [[Category: Wang, J.]] | ||
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[[Category: x-ray crystallography]] | [[Category: x-ray crystallography]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:02:27 2008'' |
Revision as of 14:02, 21 February 2008
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Structure of D153H/K328W E. coli alkaline phosphatase in presence of cobalt at 1.77 A resolution
Overview
Escherichia coli alkaline phosphatase exhibits maximal activity when Zn(2+) fills the M1 and M2 metal sites and Mg(2+) fills the M3 metal site. When other metals replace the zinc and magnesium, the catalytic efficiency is reduced by more than 5000-fold. Alkaline phosphatases from organisms such as Thermotoga maritima and Bacillus subtilis require cobalt for maximal activity and function poorly with zinc and magnesium. Previous studies have shown that the D153H alkaline phosphatase exhibited very little activity in the presence of cobalt, while the K328W and especially the D153H/K328W mutant enzymes can use cobalt for catalysis. To understand the structural basis for the altered metal specificity and the ability of the D153H/K328W enzyme to utilize cobalt for catalysis, we determined the structures of the inactive wild-type E. coli enzyme with cobalt (WT_Co) and the structure of the active D153H/K328W enzyme with cobalt (HW_Co). The structural data reveal differences in the metal coordination and in the strength of the interaction with the product phosphate (P(i)). Since release of P(i) is the slow step in the mechanism at alkaline pH, the enhanced binding of P(i) in the WT_Co structure explains the observed decrease in activity, while the weakened binding of P(i) in the HW_Co structure explains the observed increase in activity. These alterations in P(i) affinity are directly related to alterations in the coordination of the metals in the active site of the enzyme.
About this Structure
1Y7A is a Single protein structure of sequence from Escherichia coli with , and as ligands. Active as Alkaline phosphatase, with EC number 3.1.3.1 Full crystallographic information is available from OCA.
Reference
Metal specificity is correlated with two crucial active site residues in Escherichia coli alkaline phosphatase., Wang J, Stieglitz KA, Kantrowitz ER, Biochemistry. 2005 Jun 14;44(23):8378-86. PMID:15938627
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