Structural highlights
Function
[DPOLL_HUMAN] Repair polymerase. Involved in base excision repair (BER) responsible for repair of lesions that give rise to abasic (AP) sites in DNA. Has both DNA polymerase and terminal transferase activities. Has a 5'-deoxyribose-5-phosphate lyase (dRP lyase) activity.[1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Insertions and deletions in coding sequences can alter the reading frame of genes and have profound biological consequences. In 1966, Streisinger proposed that these mutations result from strand slippage, which in repetitive sequences generates misaligned intermediates stabilized by correct base pairing that support polymerization. We report here crystal structures of human DNA polymerase lambda, which frequently generates deletion mutations, bound to such intermediates. Each contains an extrahelical template nucleotide upstream of the active site. Surprisingly, the extra nucleotide, even when combined with an adjacent mismatch, does not perturb polymerase active site geometry, which is indistinguishable from that for correctly aligned strands. These structures reveal how pol lambda can polymerize on substrates with minimal homology during repair of double-strand breaks and represent strand-slippage intermediates consistent with Streisinger's classical hypothesis. They are thus relevant to the origin of single-base deletions, a class of mutations that can confer strong biological phenotypes.
Structural analysis of strand misalignment during DNA synthesis by a human DNA polymerase.,Garcia-Diaz M, Bebenek K, Krahn JM, Pedersen LC, Kunkel TA Cell. 2006 Jan 27;124(2):331-42. PMID:16439207[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Garcia-Diaz M, Bebenek K, Kunkel TA, Blanco L. Identification of an intrinsic 5'-deoxyribose-5-phosphate lyase activity in human DNA polymerase lambda: a possible role in base excision repair. J Biol Chem. 2001 Sep 14;276(37):34659-63. Epub 2001 Jul 16. PMID:11457865 doi:10.1074/jbc.M106336200
- ↑ Maga G, Ramadan K, Locatelli GA, Shevelev I, Spadari S, Hubscher U. DNA elongation by the human DNA polymerase lambda polymerase and terminal transferase activities are differentially coordinated by proliferating cell nuclear antigen and replication protein A. J Biol Chem. 2005 Jan 21;280(3):1971-81. Epub 2004 Nov 10. PMID:15537631 doi:10.1074/jbc.M411650200
- ↑ Garcia-Diaz M, Bebenek K, Krahn JM, Pedersen LC, Kunkel TA. Structural analysis of strand misalignment during DNA synthesis by a human DNA polymerase. Cell. 2006 Jan 27;124(2):331-42. PMID:16439207 doi:10.1016/j.cell.2005.10.039
