The novel human DNA helicase hFBH1 is an F-box protein.
We have identified a novel DNA helicase in humans that belongs to members of the superfamily I helicase and found that it contains a well conserved F-box motif at its N terminus. We have named the enzyme hFBH1 (human F-box DNA helicase 1). Recombinant hFBH1, containing glutathione S-transferase at the N terminus, was expressed in Sf9 cells and purified. In this report, we show that hFBH1 exhibited DNA-dependent ATPase and DNA unwinding activities that displace duplex DNA in the 3' to 5' direction. The hFBH1 enzyme interacted with human SKP1 and formed an SCF (SKP1/Cullin/F-box) complex together with human Cullin and ROC1. In addition, the SCF complex containing hFBH1 as an F-box protein displayed ubiquitin ligase activity. We demonstrate that hFBH1 is the first F-box protein that possesses intrinsic enzyme activity. The potential role of the F-box motif and the helicase activity of the enzyme are discussed with regard to regulation of DNA metabolism.
Kim
Jaehoon
J
National Creative Research Initiative Center for Cell Cycle Control, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Chunchun-Dong, Changan-Ku, Suwon, Kyunggi-Do, 440-746, Korea.
Kim
Jeong-Hoon
JH
Lee
Sung-Hak
SH
Kim
Do-Hyung
DH
Kang
Ho-Young
HY
Bae
Sung-Ho
SH
Pan
Zhen-Qiang
ZQ
Seo
Yeon-Soo
YS
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D004265:DNA Helicases / Q000737:chemistry* / Q000378:metabolism; D017931:DNA Primers; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D006801:Humans; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D018411:Spodoptera; D014162:Transfection
D017931:DNA Primers; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; C027093:TraI protein, E coli; D004265:DNA Helicases; C464443:FBH1 protein, human