1rys
REPLICATION OF A CIS-SYN THYMINE DIMER AT ATOMIC RESOLUTION
OverviewOverview
Ultraviolet light damages DNA by catalysing covalent bond formation between adjacent pyrimidines, generating cis-syn cyclobutane pyrimidine dimers (CPDs) as the most common lesion. CPDs block DNA replication by high-fidelity DNA polymerases, but they can be efficiently bypassed by the Y-family DNA polymerase pol eta. Mutations in POLH encoding pol eta are implicated in nearly 20% of xeroderma pigmentosum, a human disease characterized by extreme sensitivity to sunlight and predisposition to skin cancer. Here we have determined two crystal structures of Dpo4, an archaeal pol eta homologue, complexed with CPD-containing DNA, where the 3' and 5' thymine of the CPD separately serves as a templating base. The 3' thymine of the CPD forms a Watson-Crick base pair with the incoming dideoxyATP, but the 5' thymine forms a Hoogsteen base pair with the dideoxyATP in syn conformation. Dpo4 retains a similar tertiary structure, but each unusual DNA structure is individually fitted into the active site for catalysis. A model of the pol eta-CPD complex built from the crystal structures of Saccharomyces cerevisiae apo-pol eta and the Dpo4-CPD complex suggests unique features that allow pol eta to efficiently bypass CPDs.
About this StructureAbout this Structure
1RYS is a Single protein structure of sequence from Sulfolobus solfataricus. This structure supersedes the now removed PDB entry 1pm8. The following page contains interesting information on the relation of 1RYS with [Thymine Dimers]. Full crystallographic information is available from OCA.
ReferenceReference
Replication of a cis-syn thymine dimer at atomic resolution., Ling H, Boudsocq F, Plosky BS, Woodgate R, Yang W, Nature. 2003 Aug 28;424(6952):1083-7. Epub 2003 Aug 6. PMID:12904819 Page seeded by OCA on Sat May 3 08:04:34 2008