TableEdit

Oliveros, M, Yáñez, RJ, Salas, ML, Salas, J, Viñuela, E and Blanco, L (1997) Characterization of an African swine fever virus 20-kDa DNA polymerase involved in DNA repair. J. Biol. Chem. 272:30899-910

African swine fever virus (ASFV) encodes a novel DNA polymerase, constituted of only 174 amino acids, belonging to the polymerase (pol) X family of DNA polymerases. Biochemical analyses of the purified enzyme indicate that ASFV pol X is a monomeric DNA-directed DNA polymerase, highly distributive, lacking a proofreading 3'-5'-exonuclease, and with a poor discrimination against dideoxynucleotides. A multiple alignment of family X DNA polymerases, together with the extrapolation to the crystal structure of mammalian DNA polymerase beta (pol beta), showed the conservation in ASFV pol X of the most critical residues involved in DNA binding, nucleotide binding, and catalysis of the polymerization reaction. Therefore, the 20-kDa ASFV pol X most likely represents the minimal functional version of an evolutionarily conserved pol beta-type DNA polymerase core, constituted by only the "palm" and "thumb" subdomains. It is worth noting that such an "unfingered" DNA polymerase is able to handle templated DNA polymerization with a considerable high fidelity at the base discrimination level. Base excision repair is considered to be a cellular defense mechanism repairing modified bases in DNA. Interestingly, the fact that ASFV pol X is able to conduct filling of a single nucleotide gap points to a putative role in base excision repair during the ASFV life cycle.

PubMed

African Swine Fever Virus/enzymology; Amino Acid Sequence; Animals; Base Sequence; Crystallography, X-Ray; DNA Repair; DNA, Viral/physiology; DNA-Directed DNA Polymerase/chemistry; DNA-Directed DNA Polymerase/metabolism; Humans; Models, Molecular; Molecular Sequence Data; Molecular Weight; Protein Conformation; Sequence Alignment