TY - JOUR
T1 - Mesoscopic analysis of motion and conformation of cross-bridges
AU - Borejdo, J.
AU - Rich, R.
AU - Midde, K.
N1 - Funding Information:
Acknowledgements Supported by NIH R01AR048622 and R01HL090786 grants and by Predoctoral Fellowship 12PRE8730003 from AHA. The transgenic and WT frozen hearts were kindly donated by Dr. James D. Potter (University of Miami, Miller School of Medicine) and Dr J. Pinto (Florida State University). We thank Amy Li for comments on the manuscript.
PY - 2012/12
Y1 - 2012/12
N2 - The orientation of a cross-bridge is widely used as a parameter in determining the state of muscle. The conventional measurements of orientation, such as that made by wide-field fluorescence microscopy, electron paramagnetic resonance (EPR) or X-ray diffraction or scattering, report the average orientation of 1012-109 myosin cross-bridges. Under conditions where all the cross-bridges are immobile and assume the same orientation, for example in normal skeletal muscle in rigor, it is possible to determine the average orientation from such global measurements. But in actively contracting muscle, where a parameter indicating orientation fluctuates in time, the measurements of the average value provide no information about cross-bridge kinetics. To avoid problems associated with averaging information from trillions of cross-bridges, it is necessary to decrease the number of observed cross-bridges to a mesoscopic value (i. e. the value affected by fluctuations around the average). In such mesoscopic regimes, the averaging of the signal is minimal and dynamic behavior can be examined in great detail. Examples of mesoscopic analysis on skeletal and cardiac muscle are provided.
AB - The orientation of a cross-bridge is widely used as a parameter in determining the state of muscle. The conventional measurements of orientation, such as that made by wide-field fluorescence microscopy, electron paramagnetic resonance (EPR) or X-ray diffraction or scattering, report the average orientation of 1012-109 myosin cross-bridges. Under conditions where all the cross-bridges are immobile and assume the same orientation, for example in normal skeletal muscle in rigor, it is possible to determine the average orientation from such global measurements. But in actively contracting muscle, where a parameter indicating orientation fluctuates in time, the measurements of the average value provide no information about cross-bridge kinetics. To avoid problems associated with averaging information from trillions of cross-bridges, it is necessary to decrease the number of observed cross-bridges to a mesoscopic value (i. e. the value affected by fluctuations around the average). In such mesoscopic regimes, the averaging of the signal is minimal and dynamic behavior can be examined in great detail. Examples of mesoscopic analysis on skeletal and cardiac muscle are provided.
KW - Fluorescence polarization
KW - Mesoscopic measurements
KW - Myosin cross-bridge orientation
UR - http://www.scopus.com/inward/record.url?scp=84873194689&partnerID=8YFLogxK
U2 - 10.1007/s12551-012-0074-y
DO - 10.1007/s12551-012-0074-y
M3 - Review article
AN - SCOPUS:84873194689
SN - 1867-2450
VL - 4
SP - 299
EP - 311
JO - Biophysical Reviews
JF - Biophysical Reviews
IS - 4
ER -