Backsteps induced by nucleotide analogs suggest the front head of kinesin is gated by strain.

ABSTRACT: The two-headed kinesin motor harnesses the energy of ATP hydrolysis to take 8-nm steps, walking processively along a microtubule, alternately stepping with each of its catalytic heads in a hand-over-hand fashion. Two persistent challenges for models of kinesin motility are to explain how the two heads are coordinated ("gated") and when the translocation step occurs relative to other events in the mechanochemical reaction cycle. To investigate these questions, we used a precision optical trap to measure the single-molecule kinetics of kinesin in the presence of substrate analogs beryllium fluoride or adenylyl-imidodiphosphate. We found that normal stepping patterns were interspersed with long pauses induced by analog binding, and that these pauses were interrupted by short-lived backsteps.

SUBMITTER: Guydosh NR 

PROVIDER: S-EPMC1472428 | biostudies-literature | 2006 May

REPOSITORIES: biostudies-literature