PcrA helicase, a prototype ATP-driven molecular motor

被引:27
作者
Dittrich, Markus [1 ]
Schulten, Klaus [1 ]
机构
[1] Univ Illinois, Beckman Inst, Theoret & Computat Biophys Grp, Urbana, IL 61801 USA
关键词
D O I
10.1016/j.str.2006.06.017
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Despite extensive studies, the mechanisms underlying molecular motor function are still poorly understood. Key to the mechanisms is the coupling of ATP hydrolysis to conformational changes of the motor protein. To investigate this coupling, we have conducted combined quantum mechanical/molecular mechanical simulations of PcrA helicase, a strikingly simple motor that translocates unidirectionally along single-stranded DNA (ssDNA). Our results reveal a close similarity in catalytic site structure and reaction pathway to those of F-1-ATPase, and these similarities include a proton relay mechanism important for efficient ATP hydrolysis and an "arginine finger" residue that is key to the coupling of the chemical reaction to protein conformational changes. By means of in silico mutation studies, we identified the residue Q254 as being crucial for the coupling of ssDNA translocation to the actual catalytic event. Based on the present result for PcrA helicase and previous findings for F-1-ATPase, we propose a general mechanism of ATP-driven molecular motor function.
引用
收藏
页码:1345 / 1353
页数:9
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