UMass Chan Affiliations
Department of PhysiologyDocument Type
Journal ArticlePublication Date
2002-12-06Keywords
ActinsAdenosine Diphosphate
Adenosine Triphosphate
Animals
Dynein ATPase
*Molecular Motor Proteins
Molecular Sequence Data
*Myosins
Protein Structure, Tertiary
Rats
Life Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
Myosin VIIA was cloned from rat kidney, and the construct (M7IQ5) containing the motor domain, IQ domain, and the coiled-coil domain as well as the full-length myosin VIIA (M7full) was expressed. The M7IQ5 contained five calmodulins. Based upon native gel electrophoresis and gel filtration, it was found that M7IQ5 was single-headed, whereas M7full was two-headed, suggesting that the tail domain contributes to form the two-headed structure. M7IQ5 had Mg(2+)-ATPase activity that was markedly activated by actin with K(actin) of 33 microm and V(max) of 0.53 s(-1) head(-1). Myosin VIIA required an extremely high ATP concentration for ATPase activity, ATP-induced dissociation from actin, and in vitro actin-translocating activity. ADP markedly inhibited the actin-activated ATPase activity. ADP also significantly inhibited the ATP-induced dissociation of myosin VIIA from actin. Consistently, ADP decreased K(actin) of the actin-activated ATPase. ADP decreased the actin gliding velocity, although ADP did not stop the actin gliding even at high concentration. These results suggest that myosin VIIA has slow ATP binding or low affinity for ATP and relatively high affinity for ADP. The directionality of myosin VIIA was determined by using the polarity-marked dual fluorescence-labeled actin filaments. It was found that myosin VIIA is a plus-directed motor.Source
J Biol Chem. 2003 Feb 14;278(7):5478-87. Epub 2002 Dec 3. Link to article on publisher's siteDOI
10.1074/jbc.M210489200Permanent Link to this Item
http://hdl.handle.net/20.500.14038/42369PubMed ID
12466270Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1074/jbc.M210489200