Molecular Mechanism of energy transduction of dynein revealed by genetic engineering, structural and enzyme kinetics studies

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Our major goal of this project is to elucidate the molecular mechanism of energy transduction of cytoplasmic dynein by genetic engineering, structural studies and ATPase kinetics analyses. Our major results are: (1) we have identified the minimal motor domain of cytoplasmic dynein and examined its structure by electron microscopy. (2) Based on ATPase kinetics, we have identified three ATPase sites and one ADP-binding site in the minimal motor domain (380kDa), among which one is the primary ATPase site and the others are regulatory sites. (3) We have identified intermediate steps of the ATPase cycle by means of stopped-flow kinetics. (4) We have discovered that the linker protruding from the core ring swings as a lever-arm at specific steps of the ATPase cycle of the primary ATPase site. (5) We have shown that structural changes of the microtubule-binding domain of dynein are induced at specific ATPase steps of the primary ATPase site. Based on these findings, we have proposed a molecular model of energy transduction of cytoplasmic dynein.