Mycobacterium smegmatis SftH exemplifies a distinctive clade of superfamily II DNA-dependent ATPases with 3' to 5' translocase and helicase activities.
Bacterial DNA helicases are nucleic acid-dependent NTPases that play important roles in DNA replication, recombination and repair. We are interested in the DNA helicases of Mycobacteria, a genus of the phylum Actinobacteria, which includes the human pathogen Mycobacterium tuberculosis and its avirulent relative Mycobacterium smegmatis. Here, we identify and characterize M. smegmatis SftH, a superfamily II helicase with a distinctive domain structure, comprising an N-terminal NTPase domain and a C-terminal DUF1998 domain (containing a putative tetracysteine metal-binding motif). We show that SftH is a monomeric DNA-dependent ATPase/dATPase that translocates 3' to 5' on single-stranded DNA and has 3' to 5' helicase activity. SftH homologs are found in bacteria representing 12 different phyla, being especially prevalent in Actinobacteria (including M. tuberculosis). SftH homologs are evident in more than 30 genera of Archaea. Among eukarya, SftH homologs are present in plants and fungi.
Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA.
Lyudmila
L
Yakovleva
Stewart
S
Shuman
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D007700:Kinetics; D008670:Metals / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D020102:Mycobacterium smegmatis / Q000201:enzymology*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D013379:Substrate Specificity
D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D008670:Metals; D000255:Adenosine Triphosphate; D004247:DNA; D000251:Adenosine Triphosphatases; D004265:DNA Helicases