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
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 ... [(full description)]
About this Structure
1E9N is a [Single protein] structure of sequence from [Homo sapiens] with PB as [ligand]. Active as [DNA-(apurinic or apyrimidinic site) lyase], with EC number [4.2.99.18]. Structure known Active Sites: PB1, PB2, PB3 and PB4. 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
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