The work described in this article is part of a NIST project studying the possible use of DNA as a picoforce standard, because enzymes build DNA with atomic precision. DNA already is used informally to calibrate atomic force microscopes. An official standard could, for the first time, enable picoscale measurements that are traceable to internationally accepted units. DNA elasticity could provide a force standard from 0.1 -10 pico-Newtons (pN), where 1 pN is the approximate weight of an E. coli cell or the force exerted by 1 milliwatt of light reflected off a mirror.
The work was supported by the Alfred P. Sloan Foundation, a Burroughs Wellcome Fund Career Award in the Biomedical Sciences, the Butcher Foundation, a W.M. Keck Grant in the RNA Sciences, NIST, and the National Science Foundation.
Non-Linear Force-Length Relationship in the ADP-Induced Contraction of Skeletal Myofibrils
Yuta Shimamoto, Waseda University
Fumiaki Kono, Waseda University
Madoka Suzuki, Consolidated Research Institute for Advanced Science and Medical Care, Waseda University
Shin'ichi Ishiwata, Waseda University
Keywords: ADP-bound cross-bridges; cooperativity; dextran; lattice spacing; length-dependent activation; sarcomere
Muscle is one of the most important organs in biological system, yet its regulatory mechanism is still not fully revealed because of its complex nature involving binding of both Ca2+ and myosin (a linear force-generating motor) to actin filament (the track protein). In this work the authors approached the mechanism of regulation by myosin molecules from a new angle. The idea was to test the effect of actin-myosin interaction on force regulation independently of Ca2+, utilizing artificial activation by ADP, a product of ATP hydrolysis, in the absence of free Ca2+. The authors carefully examined the properties of activation by simultaneously monit
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