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1e9n
From Proteopedia
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'''A SECOND DIVALENT METAL ION IN THE ACTIVE SITE OF A NEW CRYSTAL FORM OF HUMAN APURINIC/APYRIMIDINIC ENDONUCLEASE, APE1, AND ITS IMPLICATIONS FOR THE CATALYTIC MECHANISM''' | '''A SECOND DIVALENT METAL ION IN THE ACTIVE SITE OF A NEW CRYSTAL FORM OF HUMAN APURINIC/APYRIMIDINIC ENDONUCLEASE, APE1, AND ITS IMPLICATIONS FOR THE CATALYTIC MECHANISM''' | ||
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==Reference== | ==Reference== | ||
Two divalent metal ions in the active site of a new crystal form of human apurinic/apyrimidinic endonuclease, Ape1: implications for the catalytic mechanism., Beernink PT, Segelke BW, Hadi MZ, Erzberger JP, Wilson DM 3rd, Rupp B, J Mol Biol. 2001 Apr 6;307(4):1023-34. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/11286553 11286553] | Two divalent metal ions in the active site of a new crystal form of human apurinic/apyrimidinic endonuclease, Ape1: implications for the catalytic mechanism., Beernink PT, Segelke BW, Hadi MZ, Erzberger JP, Wilson DM 3rd, Rupp B, J Mol Biol. 2001 Apr 6;307(4):1023-34. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/11286553 11286553] | ||
| - | [[Category: DNA-(apurinic or apyrimidinic site) lyase]] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: Rupp, B.]] | [[Category: Rupp, B.]] | ||
[[Category: Segelke, B W.]] | [[Category: Segelke, B W.]] | ||
| - | [[Category: | + | [[Category: Abasic endonuclease]] |
| - | [[Category: | + | [[Category: Alpha]] |
| - | [[Category: | + | [[Category: Ape1]] |
| - | [[Category: | + | [[Category: Base excision repair]] |
| - | [[Category: | + | [[Category: Beta sandwich]] |
| - | [[Category: | + | [[Category: Dna repair endonuclease]] |
| - | [[Category: | + | [[Category: Hap1]] |
| - | [[Category: | + | [[Category: Ref-1]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 14:50:24 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 11:50, 2 May 2008
A SECOND DIVALENT METAL ION IN THE ACTIVE SITE OF A NEW CRYSTAL FORM OF HUMAN APURINIC/APYRIMIDINIC ENDONUCLEASE, APE1, AND ITS IMPLICATIONS FOR THE CATALYTIC MECHANISM
Overview
The major human abasic endonuclease, Ape1, is an essential DNA repair enzyme that initiates the removal of apurinic/apyrimidinic sites from DNA, excises 3' replication-blocking moieties, and modulates the DNA binding activity of several transcriptional regulators. We have determined the X-ray structure of the full-length human Ape1 enzyme in two new crystal forms, one at neutral and one at acidic pH. The new structures are generally similar to the previously determined structure of a truncated Ape1 protein, but differ in the conformation of several loop regions and in spans of residues with weak electron density. While only one active-site metal ion is present in the structure determined at low pH, the structure determined from a crystal grown at the pH optimum of Ape1 nuclease activity, pH 7.5, has two metal ions bound 5 A apart in the active site. Enzyme kinetic data indicate that at least two metal-binding sites are functionally important, since Ca(2+) exhibits complex stimulatory and inhibitory effects on the Mg(2+)-dependent catalysis of Ape1, even though Ca(2+) itself does not serve as a cofactor. In conjunction, the structural and kinetic data suggest that Ape1 catalyzes hydrolysis of the DNA backbone through a two metal ion-mediated mechanism.
About this Structure
1E9N is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Two divalent metal ions in the active site of a new crystal form of human apurinic/apyrimidinic endonuclease, Ape1: implications for the catalytic mechanism., Beernink PT, Segelke BW, Hadi MZ, Erzberger JP, Wilson DM 3rd, Rupp B, J Mol Biol. 2001 Apr 6;307(4):1023-34. PMID:11286553 Page seeded by OCA on Fri May 2 14:50:24 2008
