The archaeal Hjm helicase has recQ-like functions, and may be involved in repair of stalled replication fork.
The archaeal Hjm is a structure-specific DNA helicase, which was originally identified in the hyperthermophilic archaeon, Pyrococcus furiosus, by in vitro screening for Holliday junction migration activity. Further biochemical analyses of the Hjm protein from P. furiosus showed that this protein preferably binds to fork-related Y-structured DNAs and unwinds their double-stranded regions in vitro, just like the E. coli RecQ protein. Furthermore, genetic analyses showed that Hjm produced in E. coli cells partially complemented the defect of functions of RecQ in a recQ mutant E. coli strain. These results suggest that Hjm may be a functional counterpart of RecQ in Archaea, in which it is necessary for the maintenance of genome integrity, although the amino acid sequences are not conserved. The functional interaction of Hjm with PCNA for its helicase activity further suggests that the Hjm works at stalled replication forks, as a member of the reconstituted replisomes to restart replication.
Fujikane
Ryosuke
R
Department of Genetic Resources Technology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Fukuoka-shi, Fukuoka 812-8581, Japan.
Shinagawa
Hideo
H
Ishino
Yoshizumi
Y
D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004258:DNA Polymerase III / Q000378:metabolism; D004260:DNA Repair / Q000235:genetics*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D005816:Genetic Complementation Test; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009690:Nucleic Acid Conformation; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011485:Protein Binding; D020027:Pyrococcus furiosus / Q000201:enzymology*; D053484:RecQ Helicases / Q000378:metabolism*; D016415:Sequence Alignment
D019843:Archaeal Proteins; D004268:DNA-Binding Proteins; D018809:Proliferating Cell Nuclear Antigen; D004247:DNA; C074904:DNA polymerase III, alpha subunit; D004258:DNA Polymerase III; D053484:RecQ Helicases