title: An unexpectedly large working stroke from chymotryptic fragments of myosin II.
abstract: Recent structural evidence indicates that the light chain domain of the myosin head (LCD) bends on the motor domain (MD) to move actin. Structural models usually assume that the actin-MD interface remains static and the possibility that part of the myosin working stroke might be produced by rotation about the acto-myosin interface has been neglected. We have used an optical trap to measure the movement produced by proteolytically shortened single rabbit skeletal muscle myosin heads (S-1(A1) and S-1(A2)). The working stroke produced by these shortened heads was more than that which the MD-LCD bend mechanism predicts from the full-length (papain) S-1's working stroke obtained under similar conditions. This result indicates that part of the working stroke may be caused by motor action at the actin-MD interface.
authors.affiliation: Department of Biology, University of York, UK.
authors.forename: J E
authors.initials: JE
authors.lastname: Molloy
authors.forename: J
authors.initials: J
authors.lastname: Kendrick-Jones
authors.forename: C
authors.initials: C
authors.lastname: Veigel
authors.forename: R T
authors.initials: RT
authors.lastname: Tregear
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002918:Chymotrypsin / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011817:Rabbits
chemical_list: D000199:Actins; D010446:Peptide Fragments; D000255:Adenosine Triphosphate; D002918:Chymotrypsin; D009218:Myosins