TY - JOUR TI - Examining kinesin processivity within a general gating framework AU - Andreasson, Johan OL AU - Milic, Bojan AU - Chen, Geng-Yuan AU - Guydosh, Nicholas R AU - Hancock, William O AU - Block, Steven M A2 - Akhmanova, Anna VL - 4 PY - 2015 DA - 2015/04/22 SP - e07403 C1 - eLife 2015;4:e07403 DO - 10.7554/eLife.07403 UR - https://doi.org/10.7554/eLife.07403 AB - Kinesin-1 is a dimeric motor that transports cargo along microtubules, taking 8.2-nm steps in a hand-over-hand fashion. The ATP hydrolysis cycles of its two heads are maintained out of phase by a series of gating mechanisms, which lead to processive runs averaging ∼1 μm. A key structural element for inter-head coordination is the neck linker (NL), which connects the heads to the stalk. To examine the role of the NL in regulating stepping, we investigated NL mutants of various lengths using single-molecule optical trapping and bulk fluorescence approaches in the context of a general framework for gating. Our results show that, although inter-head tension enhances motor velocity, it is crucial neither for inter-head coordination nor for rapid rear-head release. Furthermore, cysteine-light mutants do not produce wild-type motility under load. We conclude that kinesin-1 is primarily front-head gated, and that NL length is tuned to enhance unidirectional processivity and velocity. KW - optical trap KW - molecular motor KW - single molecule JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -