RecQ helicases unwind DNA in an ATP-dependent manner. Sgs1 has a HRDC (helicase and RNaseD C-terminal) domain which modulates the helicase function via auxiliary contacts to DNA [1].

1: The three-dimensional structure of the HRDC domain and implications for the Werner and Bloom syndrome proteins. Liu Z, Macias MJ, Bottomley MJ, Stier G, Linge JP, Nilges M, Bork P, Sattler M; Structure. 1999;7:1557-1566. PMID:10647186