Summary
PDB 1BIX deposited: 1998-06-19 modified: 2009-02-24
Title THE CRYSTAL STRUCTURE OF THE HUMAN DNA REPAIR ENDONUCLEASE HAP1 SUGGESTS THE RECOGNITION OF EXTRA-HELICAL DEOXYRIBOSE AT DNA ABASIC SITES
Authors de La Fortelle, E., Freemont, P.S., Gorman, M.A., Hickson, I.D., Mol, C.D., Morera, S., Rothwell, D.G., Tainer, J.A.
Method X-RAY DIFFRACTION
Structure factors resolution 2.2 rfactor 0.184 rfree 0.269
DPI 0.64 theoretical min: 0.27
Citations

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.

EMBO J. 1997 Nov; 16(21):6548-6558 doi:10.1093/emboj/16.21.6548

Cross References
Database source Identifier Description
PubMed 9351835 EMJODG
Biomolecule Structure Assembly Serial Assembly Type Conformational State Chains Ligands Atoms
1BIX/0 1BIX 0 monomer 0 1 5 2037