Kinetic study of the DNA annealing properties of RECQ5β helicase

• 来源期刊: 科学通报(英文版)
• 学科: 生物学
• 年，卷（期）: 2012,（11）
• 页码范围: 1280-1287
• 页数: 8页
• 分类号: Q55
• 语种: 中文

摘要

RecQ family helicases are critical for maintaining genomic integrity. Many RecQ family helicases not only unwind duplex, and other more complicated DNA structures, but also possess, interestingly, DNA annealing (strand pairing) activity. Here, we systematically investigated the DNA annealing properties of RECQ5β by measuring DNA annealing kinetics, equilibrium DNA binding, and kinetics of dissociation from ssDNA. RECQ5β catalyzed DNA annealing most efficiently when the enzyme molecules covered approximately 40%-50% of the DNA strand, in the absence or presence of different nucleotide cofactors (AMPPNP, ATPγS, or ADP) under our buffer conditions. A comparative study with RECQ5β1-662 confirmed that the C-terminal region of RECQ5β was essential for its high DNA annealing activity. These results contribute to our understanding of the mechanism of DNA annealing catalyzed by RecQ family helicases.