Kinetic study of the DNA annealing properties of RECQ5β helicase  

作　　者：DING XiuYan XU YaNan LI Wei WANG PengYe XI XuGuang DOU ShuoXing 

机构地区：[1]College of Life Sciences,Northwest A&F University,Yangling 712100,China [2]Laboratory of Soft Matter Physics,Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [3]Institut Curie-Section de Recherche,Centre Universitaire,BStiment 110,F-91405 Orsay,France

出　　处：《Chinese Science Bulletin》2012年第11期1280-1287,共8页

基　　金：supported by the National Natural Science Foundation of China (10834014);the National Basic Research Program of China (2009CB930704)

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.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 sys- tematically investigated the DNA annealing properties of RECQ513 by measuring DNA annealing kinetics, equilibrium DNA binding, and kinetics of dissociation from ssDNA. RECQ513 catalyzed DNA annealing most efficiently when the enzyme mole- cules 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 RECQ5β^1-662 confirmed that the C-terminal region of RECQ5[3 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.

关 键 词：DNA结构 动力学性质 解旋酶 退火 属性 催化机制 单链DNA DNA结合 

分 类 号：Q55[生物学—生物化学]