TY - JOUR
T1 - Effect of negative mechanical stress on the orientation of myosin cross-bridges in muscle fibers
AU - Burghardt, T. P.
AU - Ajtai, K.
PY - 1989
Y1 - 1989
N2 - The effect of positive and negative stress on myosin cross-bridge orientation in glycerinated muscle fibers was investigated by using fluorescence polarization spectroscopy of the emission from the covalent label tetramethylrhodamine-5-(and -6-)-iodoacetamide (IATR) specifically modifying sulfhydryl one (SH1) on the myosin heavy chain. Positive tension was applied by stretching the fiber in rigor. Negative tension was applied in two steps by using a protocol introduced by Goldman et al. [Goldman, Y.E., McCray, J.A. & Vallette, D.P. (1988) J. Physiol. (London) 398, 75P]: relaxing a fiber at resting length and stretching it until the relaxed tension is appreciable and then placing the fiber in rigor and releasing the tension onto the rigor cross-bridges. We found, as have others, that positive tension has no effect on the fluorescence polarization spectrum from the SH1-bound probe, indicating that the cross-bridge does not rotate under these conditions. Negative tension, however, causes a change in the fluorescence polarization spectrum that indicates a probe rotation. The changes in the polarization spectrum from negative stress are partially reversed by the subsequent application of positive stress. It appears that negative tension strains the cross-bridge, or the cross-bridge domain containing SH1, and causes it to rotate.
AB - The effect of positive and negative stress on myosin cross-bridge orientation in glycerinated muscle fibers was investigated by using fluorescence polarization spectroscopy of the emission from the covalent label tetramethylrhodamine-5-(and -6-)-iodoacetamide (IATR) specifically modifying sulfhydryl one (SH1) on the myosin heavy chain. Positive tension was applied by stretching the fiber in rigor. Negative tension was applied in two steps by using a protocol introduced by Goldman et al. [Goldman, Y.E., McCray, J.A. & Vallette, D.P. (1988) J. Physiol. (London) 398, 75P]: relaxing a fiber at resting length and stretching it until the relaxed tension is appreciable and then placing the fiber in rigor and releasing the tension onto the rigor cross-bridges. We found, as have others, that positive tension has no effect on the fluorescence polarization spectrum from the SH1-bound probe, indicating that the cross-bridge does not rotate under these conditions. Negative tension, however, causes a change in the fluorescence polarization spectrum that indicates a probe rotation. The changes in the polarization spectrum from negative stress are partially reversed by the subsequent application of positive stress. It appears that negative tension strains the cross-bridge, or the cross-bridge domain containing SH1, and causes it to rotate.
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U2 - 10.1073/pnas.86.14.5366
DO - 10.1073/pnas.86.14.5366
M3 - Article
C2 - 2526336
AN - SCOPUS:0024335594
SN - 0027-8424
VL - 86
SP - 5366
EP - 5370
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 - 14
ER -