A mitochondrial DNA polymerase from embryos of Drosophila melanogaster. Purification, subunit structure, and partial characterization.
The mitochondrial DNA polymerase has been purified to near-homogeneity from early embryos of Drosophila melanogaster. Sodium dodecyl sulfate gel electrophoresis of the highly purified enzyme reveals two polypeptides with molecular masses of 125,000 and 35,000 daltons, in a ratio of 1:1. The enzyme has a sedimentation coefficient of 7.6 S and a Stokes radius of 51 A. Taken together, the data suggest that the D. melanogaster DNA polymerase gamma is a heterodimer. DNA polymerase activity gel analysis has allowed the assignment of the DNA polymerization function to the large subunit. The DNA polymerase exhibits a remarkable ability to utilize efficiently a variety of template-primers including gapped DNA, poly(rA).oligo(dT) and singly primed phi X174 DNA. Both the crude and the highly purified enzymes are stimulated by KCl, and inhibited by dideoxythymidine triphosphate and by N-ethylmaleimide. Thus, the catalytic properties of the near-homogeneous Drosophila enzyme are consistent with those of DNA polymerase gamma as partially purified from several vertebrates.
D000818:Animals; D004259:DNA-Directed DNA Polymerase / Q000302:isolation & purification* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000196:embryology / Q000201:enzymology*; D004625:Embryo, Nonmammalian / Q000201:enzymology; D007700:Kinetics; D046911:Macromolecular Substances; D008928:Mitochondria / Q000201:enzymology*; D008970:Molecular Weight; D011487:Protein Conformation; D013379:Substrate Specificity; D013698:Templates, Genetic
D046911:Macromolecular Substances; D004259:DNA-Directed DNA Polymerase