title: Human Rad54B is a double-stranded DNA-dependent ATPase and has biochemical properties different from its structural homolog in yeast, Tid1/Rdh54.
abstract: The RAD52 epistasis group genes are involved in homologous recombination, and they are conserved from yeast to humans. We have cloned a novel human gene, RAD54B, which is homologous to yeast and human RAD54. Human Rad54B (hRad54B) shares high homology with human Rad54 (hRad54) in the central region containing the helicase motifs characteristic of the SNF2/SWI2 family of proteins, but the N-terminal domain is less conserved. In yeast, another RAD54 homolog, TID1/RDH54, plays a role in recombination. Tid1/Rdh54 interacts with yeast Rad51 and a meiosis-specific Rad51 homolog, Dmc1. The N-terminal domain of hRad54B shares homology with that of Tid1/Rdh54, suggesting that Rad54B may be the human counterpart of Tid1/Rdh54. We purified the hRad54 and hRad54B proteins from baculovirus-infected insect cells and examined their biochemical properties. hRad54B, like hRad54, is a DNA-binding protein and hydrolyzes ATP in the presence of double-stranded DNA, though its rate of ATP hydrolysis is lower than that of hRad54. Human Rad51 interacts with hRad54 and enhances its ATPase activity. In contrast, neither human Rad51 nor Dmc1 directly interacts with hRad54B. Although hRad54B is the putative counterpart of Tid1/Rdh54, our findings suggest that hRad54B behaves differently from Tid1/Rdh54.
authors.affiliation: Department of Molecular Pathology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Tanaka
authors.forename: Wataru
authors.initials: W
authors.lastname: Kagawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Kinebuchi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kurumizaka
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Miyagawa
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins; D004247:DNA / Q000378:metabolism*; D004265:DNA Helicases; D045643:DNA Repair Enzymes; D026942:DNA Topoisomerases; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D017434:Protein Structure, Tertiary; D051135:Rad51 Recombinase; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D018411:Spodoptera / Q000235:genetics
chemical_list: D018797:Cell Cycle Proteins; C513033:DMC1 protein, S cerevisiae; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; C491221:RAD54B protein, human; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D000251:Adenosine Triphosphatases; C074556:DMC1 protein, human; C075468:RAD54 protein, S cerevisiae; D004265:DNA Helicases; D026942:DNA Topoisomerases; C541336:RDH54 protein, S cerevisiae; D045643:DNA Repair Enzymes