Human DNA polymerase lambda (Pol lambda) is a family X member with low frameshift fidelity that has been suggested to perform gap-filling DNA synthesis during base excision repair and during repair of broken ends with limited homology. Here, we present a 2.1 A crystal structure of the catalytic core of Pol lambda in complex with DNA containing a two nucleotide gap. Pol lambda makes limited contacts with the template strand at the polymerase active site, and superimposition with Pol beta in a ternary complex suggests a shift in the position of the DNA at the active site that is reminiscent of a deletion intermediate. Surprisingly, Pol lambda can adopt a closed conformation, even in the absence of dNTP binding. These observations have implications for the catalytic mechanism and putative DNA repair functions of Pol lambda.
A structural solution for the DNA polymerase lambda-dependent repair of DNA gaps with minimal homology.,Garcia-Diaz M, Bebenek K, Krahn JM, Blanco L, Kunkel TA, Pedersen LC Mol Cell. 2004 Feb 27;13(4):561-72. PMID:14992725
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↑ Garcia-Diaz M, Bebenek K, Krahn JM, Blanco L, Kunkel TA, Pedersen LC. A structural solution for the DNA polymerase lambda-dependent repair of DNA gaps with minimal homology. Mol Cell. 2004 Feb 27;13(4):561-72. PMID:14992725