DNA topoisomerase V is a relative of eukaryotic topoisomerase I from a hyperthermophilic prokaryote.
The DNA topoisomerases are ubiquitous enzymes that fulfil vital roles in the replication, transcription and recombination of DNA by carrying out DNA-strand passage reactions. Here we characterize a prokaryotic counterpart to the eukaryotic topoisomerase I in the hyperthermophilic methanogen Methanopyrus kandleri. The new enzyme, called topoisomerase V, has the following properties in common with eukaryotic topoisomerase I, which distinguish it from all other known prokaryotic topoisomerases: (1) its activity is Mg(2+)-independent; (2) it relaxes both negatively and positively supercoiled DNA; (3) it makes a covalent complex with the 3' end of the broken DNA strand; and (4) it is recognized by antibody raised against human topoisomerase I. Eukaryotic-like enzymes have been discovered in some hyperthermophilic prokaryotes, namely the eocytes and the extremely thermophilic archaebacteria, and hyperthermophilic homologues of eukaryotic DNA polymerase-alpha, transcription factor IIB and DNA ligase have all been reported. Thus our findings support the idea that some essential parts of the eukaryotic transcription-translation and replication machineries were in place before the emergence of eukaryotes, and that the closest living relatives of eukaryotes may be hyperthermophiles.
Slesarev
A I
AI
Molecular Biology Institute, University of California, Los Angeles 90024.
Stetter
K O
KO
Lake
J A
JA
Gellert
M
M
Krah
R
R
Kozyavkin
S A
SA
D001483:Base Sequence; D003429:Cross Reactions; D004247:DNA / Q000378:metabolism; D004264:DNA Topoisomerases, Type I / Q000145:classification / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism*; D004278:DNA, Superhelical / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D019605:Euryarchaeota / Q000201:enzymology*; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D008969:Molecular Sequence Data; D011489:Protein Denaturation; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013696:Temperature
D004278:DNA, Superhelical; D004247:DNA; C082698:DNA topoisomerase V; D004264:DNA Topoisomerases, Type I; D008274:Magnesium