1bix
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THE CRYSTAL STRUCTURE OF THE HUMAN DNA REPAIR ENDONUCLEASE HAP1 SUGGESTS THE RECOGNITION OF EXTRA-HELICAL DEOXYRIBOSE AT DNA ABASIC SITES
OverviewOverview
The structure of the major human apurinic/ apyrimidinic endonuclease, (HAP1) has been solved at 2.2 A resolution. The enzyme consists of two, symmetrically related domains of similar topology and has significant, structural similarity to both bovine DNase I and its Escherichia coli, homologue exonuclease III (EXOIII). A structural comparison of these, enzymes reveals three loop regions specific to HAP1 and EXOIII. These loop, regions apparently act in DNA abasic site (AP) recognition and cleavage, since DNase I, which lacks these loops, correspondingly lacks AP site, specificity. The HAP1 structure furthermore suggests a mechanism for AP, site binding which involves the recognition of the deoxyribose moiety in, an extrahelical conformation, rather than a 'flipped-out' base opposite, the AP site.
About this StructureAbout this Structure
1BIX is a Single protein structure of sequence from Homo sapiens with SM and PT as ligands. Active as DNA-(apurinic or apyrimidinic site) lyase, with EC number 4.2.99.18 Structure known Active Site: ROX. Full crystallographic information is available from OCA.
ReferenceReference
The crystal structure of the human DNA repair endonuclease HAP1 suggests the recognition of extra-helical deoxyribose at DNA abasic sites., Gorman MA, Morera S, Rothwell DG, de La Fortelle E, Mol CD, Tainer JA, Hickson ID, Freemont PS, EMBO J. 1997 Nov 3;16(21):6548-58. PMID:9351835
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