The single minichromosome maintenance protein of Methanobacterium thermoautotrophicum DeltaH contains DNA helicase activity.
Previous studies have identified an ATP-dependent DNA helicase activity intrinsic to the human minichromosome maintenance (MCM) complex, composed of MCM subunits 4, 6, and 7 [Ishimi, Y. (1997) J. Biol. Chem. 272, 24508-24513]. In contrast to the presence of multiple MCM genes (at least six) in eukaryotes, the archaeon Methanobacterium thermoautotrophicum DeltaH (mth) genome contains a single open reading frame coding for an MCM protein. In this study we report the isolation of the mthMCM protein overexpressed in Escherichia coli. The purified recombinant protein was found to exist in both multimeric ( approximately 10(3) kDa) and monomeric (76 kDa) forms. Both forms of the protein bind to single-stranded DNA, hydrolyze ATP in the presence of DNA, and possess 3'-to-5' ATP-dependent DNA helicase activities. Thus, a single mthMCM protein contains biochemical properties identical to those associated with the eukaryotic MCM4, -6, and -7 complex. These results suggest that the characterization of the mthMCM protein and its multiple forms may contribute to our understanding of the role of MCM helicase activity in eukaryotic chromosomal DNA replication.
Kelman
Z
Z
Program of Molecular Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
Lee
J K
JK
Hurwitz
J
J
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D019843:Archaeal Proteins / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D019847:Chromosomes, Archaeal / Q000378:metabolism; D004265:DNA Helicases / Q000378:metabolism*; D004261:DNA Replication; D019641:DNA, Archaeal / Q000378:metabolism; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D005057:Eukaryotic Cells / Q000201:enzymology; D017014:Methanobacterium / Q000201:enzymology*; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7; D009687:Nuclear Proteins; D011487:Protein Conformation; D029701:Saccharomyces cerevisiae Proteins
D019843:Archaeal Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D019641:DNA, Archaeal; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D004265:DNA Helicases; C092802:MCM4 protein, S cerevisiae; C491207:MCM6 protein, S cerevisiae; C491088:MCM7 protein, S cerevisiae; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7; C403162:MCM protein, Methanobacterium thermoautotrophicum