The Q motif of a viral packaging motor governs its force generation and communicates ATP recognition to DNA interaction.

ABSTRACT: A key step in the assembly of many viruses is the packaging of DNA into preformed procapsids by an ATP-powered molecular motor. To shed light on the motor mechanism we used single-molecule optical tweezers measurements to study the effect of mutations in the large terminase subunit in bacteriophage lambda on packaging motor dynamics. A mutation, K84A, in the putative ATPase domain driving DNA translocation was found to decrease motor velocity by approximately 40% but did not change the force dependence or decrease processivity substantially. These findings support the hypothesis that a deviant "Walker A-like" phosphate-binding motif lies adjacent to residue 84. Another mutation, Y46F, was also found to decrease motor velocity by approximately 40% but also increase slipping during DNA trans

SUBMITTER: Tsay JM 

PROVIDER: S-EPMC2732826 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature