HUMAN NUCLEOTIDE EXCISION-REPAIR PROTEIN XPA - EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE EVIDENCE FOR A METAL-BINDING DOMAIN

Citation
Nj. Hess et al., HUMAN NUCLEOTIDE EXCISION-REPAIR PROTEIN XPA - EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE EVIDENCE FOR A METAL-BINDING DOMAIN, Protein science, 7(9), 1998, pp. 1970-1975
Citations number
52
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biology
Journal title
ISSN journal
0961-8368
Volume
7
Issue
9
Year of publication
1998
Pages
1970 - 1975
Database
ISI
SICI code
0961-8368(1998)7:9<1970:HNEPX->2.0.ZU;2-W
Abstract
The ubiquitous, multi-enzyme, nucleotide excision repair (NER) pathway is responsible for correcting a wide range of chemically and structur ally distinct DNA lesions in the eukaryotic genome. Human XPA, a 31 kD a, zinc-associated protein, is thought to play a major NER role in the recognition of damaged DNA and the recruitment of other proteins, inc luding RPA, ERCC1, and TFIIH, to repair the damage. Sequence analyses and genetic evidence suggest that zinc is associated with a C4-type mo tif, C105-X-2-C108-X-17-C126-X-2-C129, located in the minimal DNA bind ing region of XPA (M98-F219). The zinc-associated motif is essential f or damaged DNA recognition. Extended X-ray absorption fine structure ( EXAFS) spectra collected on the zinc associated minimal DNA-binding do main of XPA (ZnXPA-MBD) show directly, for the first time, that the zi nc is coordinated to the sulfur atoms of four cysteine residues with a n average Zn-S bond length of 2.34 +/- 0.01 Angstrom. XPA-MBD was also expressed in minimal medium supplemented with cobalt nitrate to yield a blue-colored protein that was primarily (>95%) cobalt associated (C oXPA-MBD). EXAFS spectra collected on CoXPA-MBD show that the cobalt i s also coordinated to the sulfur atoms of four cysteine residues with an average Co-S bond length of 2.33 +/- 0.02 Angstrom.