TY - JOUR
T1 - A large and distinct rotation of the myosin light chain domain occurs upon muscle contraction
AU - Baker, Josh E.
AU - Brust-Mascher, Ingrid
AU - Ramachandran, Sampath
AU - Laconte, Leslie E.W.
AU - Thomas, David D.
PY - 1998/3/17
Y1 - 1998/3/17
N2 - For more than 30 years, the fundamental goal in molecular motility has been to resolve force-generating motor protein structural changes. Although low-resolution structural studies have provided evidence for force-generating myosin rotations upon muscle activation, these studies did not resolve structural states of myosin in contracting muscle. Using electron paramagnetic resonance, we observed two distinct orientations of a spin label attached specifically to a single site on the light chain domain of myosin in relaxed scallop muscle fibers. The two probe orientations, separated by a 36°± 5°axial rotation, did not change upon muscle activation, but the distribution between them changed substantially, indicating that a fraction (17% ± 2%) of myosin heads undergoes a large (at least 30°) axial rotation of the myosin light chain domain upon force generation and muscle contraction. The resulting model helps explain why this observation has remained so elusive and provides insight into the mechanisms by which motor protein structural transitions drive molecular motility.
AB - For more than 30 years, the fundamental goal in molecular motility has been to resolve force-generating motor protein structural changes. Although low-resolution structural studies have provided evidence for force-generating myosin rotations upon muscle activation, these studies did not resolve structural states of myosin in contracting muscle. Using electron paramagnetic resonance, we observed two distinct orientations of a spin label attached specifically to a single site on the light chain domain of myosin in relaxed scallop muscle fibers. The two probe orientations, separated by a 36°± 5°axial rotation, did not change upon muscle activation, but the distribution between them changed substantially, indicating that a fraction (17% ± 2%) of myosin heads undergoes a large (at least 30°) axial rotation of the myosin light chain domain upon force generation and muscle contraction. The resulting model helps explain why this observation has remained so elusive and provides insight into the mechanisms by which motor protein structural transitions drive molecular motility.
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U2 - 10.1073/pnas.95.6.2944
DO - 10.1073/pnas.95.6.2944
M3 - Article
C2 - 9501195
AN - SCOPUS:0032539847
SN - 0027-8424
VL - 95
SP - 2944
EP - 2949
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 6
ER -