Mollicutes DNA polymerases: characterization of a single enzyme from Mycoplasma mycoides and Ureaplasma urealyticum and of three enzymes from Acholeplasma laidlawii.
The DNA polymerase activity of different members of Mollicutes was studied. A single DNA polymerase was found in Mycoplasma mycoides and Ureaplasma urealyticum, type species of the genera Mycoplasma and Ureaplasma, and was compared with the previously described Mycoplasma orale enzyme. Most of their properties were comparable; an immunological relationship was demonstrated between M. orale and M. mycoides enzymes by immunoblotting. In contrast to these results, three different DNA polymerases were purified in Acholeplasma laidlawii, type species of the genus Acholeplasma which, in this aspect, resembles the genus Spiroplasma. A 3'-5' exonuclease activity was found in the different purified preparations. In M. mycoides, M. orale and one of the three A. laidlawii preparations, the 3'-5' exonuclease could be separated from the DNA polymerase by non-denaturing PAGE. The presence of a single DNA polymerase seems to be a typical feature of the Mycoplasmataceae, which include the genera Mycoplasma and Ureaplasma, in contrast to the occurrence of three enzymes within the Acholeplasmataceae and Spiroplasmataceae. These results are in agreement with the phylogenetic tree of Mollicutes proposed from their 5 S and 16 S rRNA sequence comparisons, in which the evolution of Acholeplasma and Spiroplasma branches led, by genome reductions, to Mycoplasma and Ureaplasma species.
Maurel
D
D
Laboratoire de Bactériologie, Université de Bordeaux II, France.
Charron
A
A
Bébéar
C
C
D000128:Acholeplasma laidlawii / Q000201:enzymology; D004259:DNA-Directed DNA Polymerase / Q000276:immunology / Q000302:isolation & purification*; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000302:isolation & purification; D007120:Immunochemistry; D009176:Mycoplasma mycoides / Q000201:enzymology; D009179:Mycoplasmatales / Q000201:enzymology*; D013045:Species Specificity; D014509:Ureaplasma / Q000201:enzymology
D004259:DNA-Directed DNA Polymerase; D005090:Exodeoxyribonucleases; D043211:Exodeoxyribonuclease V