Saccharomyces cerevisiae Hrq1 requires a long 3 Prime -tailed DNA substrate for helicase activity

• Published in: Biochemical and biophysical research communications Vol. 427; no. 3
• Main Authors: Kwon, Sung-Hun, Choi, Do-Hee, Lee, Rina, Bae, Sung-Ho
• Format: Journal Article
• Language: English
• Published: United States 26-10-2012
• Subjects: 60 APPLIED LIFE SCIENCES; ANNEALING; BACTERIA; DNA; METABOLISM; PROTEINS; RECOMBINATION; SACCHAROMYCES CEREVISIAE; SUBSTRATES
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/J.BBRC.2012.09.109

Highlights: Black-Right-Pointing-Pointer Hrq1 has intrinsic 3 Prime -5 Prime helicase and DNA strand annealing activities. Black-Right-Pointing-Pointer Hrq1 requires a long 3 Prime -tail for efficient DNA unwinding. Black-Right-Pointing-Pointer Helicase activity of Hrq1 is stimulated by a fork structure. Black-Right-Pointing-Pointer Hrq1 is a moderately processive helicase. -- Abstract: RecQ helicases are well conserved proteins from bacteria to human and function in various DNA metabolism for maintenance of genome stability. Five RecQ helicases are found in humans, whereas only one RecQ helicase has been described in lower eukaryotes. However, recent studies predicted the presence of a second RecQ helicase, Hrq1, in fungal genomes and verified it as a functional gene in fission yeast. Here we show that 3 Prime -5 Prime helicase activity is intrinsically associated with Hrq1 of Saccharomyces cerevisiae. We also determined several biochemical properties of Hrq1 helicase distinguishable from those of other RecQ helicase members. Hrq1 is able to unwind relatively long duplex DNA up to 120-bp and is significantly stimulated by a preexisting fork structure. Further, the most striking feature of Hrq1 is its absolute requirement for a long 3 Prime -tail ( Greater-Than-Or-Slanted-Equal-To 70-nt) for efficient unwinding of duplex DNA. We also found that Hrq1 has potent DNA strand annealing activity. Our results indicate that Hrq1 has vigorous helicase activity that deserves further characterization to expand our understanding of RecQ helicases.