The load dependence of kinesin's mechanical cycle. Export

@article{CoppinCM_LoadDependenceKinesin_PNAS_1997, abstract = {Kinesin is a dimeric motor protein that transports organelles in a stepwise manner toward the plus-end of microtubules by converting the energy of ATP hydrolysis into mechanical work. External forces can influence the behavior of kinesin, and force-velocity curves have shown that the motor will slow down and eventually stall under opposing loads of approximately 5 pN. Using an in vitro motility assay in conjunction with a high-resolution optical trapping microscope, we have examined the behavior of individual kinesin molecules under two previously unexplored loading regimes: super-stall loads (>5 pN) and forward (plus-end directed) loads. Whereas some theories of kinesin function predict a reversal of directionality under high loads, we found that kinesin does not walk backwards under loads of up to 13 pN, probably because of an irreversible transition in the mechanical cycle. We also found that this cycle can be significantly accelerated by forward loads under a wide range of ATP concentrations. Finally, we noted an increase in kinesin's rate of dissociation from the microtubule with increasing load, which is consistent with a load dependent partitioning between two recently described kinetic pathways: a coordinated-head pathway (which leads to stepping) and an independent-head pathway (which is static).}, author = {Coppin, C. M. and Pierce, D. W. and Hsu, L. and Vale, R. D.}, citeulike-article-id = {3362990}, citeulike-linkout-0 = {http://view.ncbi.nlm.nih.gov/pubmed/9238012}, citeulike-linkout-1 = {http://www.hubmed.org/display.cgi?uids=9238012}, day = {5}, issn = {0027-8424}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, keywords = {dependence, kinesin, load}, month = {August}, number = {16}, pages = {8539--8544}, posted-at = {2008-10-01 15:44:37}, priority = {0}, title = {The load dependence of kinesin's mechanical cycle.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/9238012}, volume = {94}, year = {1997} }

TY - JOUR ID - CoppinCM_LoadDependenceKinesin_PNAS_1997 L3 - citeulike-article-id:3362990 N2 - Kinesin is a dimeric motor protein that transports organelles in a stepwise manner toward the plus-end of microtubules by converting the energy of ATP hydrolysis into mechanical work. External forces can influence the behavior of kinesin, and force-velocity curves have shown that the motor will slow down and eventually stall under opposing loads of approximately 5 pN. Using an in vitro motility assay in conjunction with a high-resolution optical trapping microscope, we have examined the behavior of individual kinesin molecules under two previously unexplored loading regimes: super-stall loads (>5 pN) and forward (plus-end directed) loads. Whereas some theories of kinesin function predict a reversal of directionality under high loads, we found that kinesin does not walk backwards under loads of up to 13 pN, probably because of an irreversible transition in the mechanical cycle. We also found that this cycle can be significantly accelerated by forward loads under a wide range of ATP concentrations. Finally, we noted an increase in kinesin's rate of dissociation from the microtubule with increasing load, which is consistent with a load dependent partitioning between two recently described kinetic pathways: a coordinated-head pathway (which leads to stepping) and an independent-head pathway (which is static). IS - 16 JF - Proceedings of the National Academy of Sciences of the United States of America SN - 0027-8424 EP - 8544 TI - The load dependence of kinesin's mechanical cycle. VL - 94 SP - 8539 KW - dependence KW - kinesin KW - load AU - Coppin, CM AU - Pierce, DW AU - Hsu, L AU - Vale, RD PY - 1997/08/05/ UR - http://view.ncbi.nlm.nih.gov/pubmed/9238012 ER -