2fz4
From Proteopedia
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Crystal Structure of the N-terminal half of Archaeoglobus Fulgidus XPB
Overview
The human xeroderma pigmentosum group B (XPB) helicase is essential for transcription, nucleotide excision repair, and TFIIH functional assembly. Here, we determined crystal structures of an Archaeoglobus fulgidus XPB homolog (AfXPB) that characterize two RecA-like XPB helicase domains and discover a DNA damage recognition domain (DRD), a unique RED motif, a flexible thumb motif (ThM), and implied conformational changes within a conserved functional core. RED motif mutations dramatically reduce helicase activity, and the DRD and ThM, which flank the RED motif, appear structurally as well as functionally analogous to the MutS mismatch recognition and DNA polymerase thumb domains. Substrate specificity is altered by DNA damage, such that AfXPB unwinds dsDNA with 3' extensions, but not blunt-ended dsDNA, unless it contains a lesion, as shown for CPD or (6-4) photoproducts. Together, these results provide an unexpected mechanism of DNA unwinding with implications for XPB damage verification in nucleotide excision repair.
About this Structure
2FZ4 is a Single protein structure of sequence from Archaeoglobus fulgidus dsm 4304. Full crystallographic information is available from OCA.
Reference
Conserved XPB core structure and motifs for DNA unwinding: implications for pathway selection of transcription or excision repair., Fan L, Arvai AS, Cooper PK, Iwai S, Hanaoka F, Tainer JA, Mol Cell. 2006 Apr 7;22(1):27-37. PMID:16600867
Page seeded by OCA on Thu Feb 21 17:26:36 2008
