Yeast mitochondrial DNA polymerase is a highly processive single-subunit enzyme.
Polymerase γ is solely responsible for fast and faithful replication of the mitochondrial genome. High processivity of the polymerase γ is often achieved by association of the catalytic subunit with accessory factors that enhance its catalytic activity and/or DNA binding. Here we characterize the intrinsic catalytic activity and processivity of the recombinant catalytic subunit of yeast polymerase γ, the Mip1 protein. We demonstrate that Mip1 can efficiently synthesize DNA stretches of up to several thousand nucleotides without dissociation from the template. Furthermore, we show that Mip1 can perform DNA synthesis on double-stranded templates utilizing a strand displacement mechanism. Our observations confirm that in contrast to its homologues in other organisms, Mip1 can function as a single-subunit replicative polymerase.
Viikov
Katrin
K
Department of Biochemistry, Institute of Molecular and Cell Biology, University of Tartu, Vanemuise 46, Tartu 51014, Estonia.
Väljamäe
Priit
P
Sedman
Juhan
J
D020134:Catalytic Domain; D004256:DNA Polymerase I / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology*; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D004272:DNA, Mitochondrial; D021122:Protein Subunits; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D004256:DNA Polymerase I; D004259:DNA-Directed DNA Polymerase; C068352:MIP1 protein, S cerevisiae