Electron tomography of cryofixed, isometrically contracting insect flight muscle reveals novel actin-myosin interactions.

ABSTRACT: Isometric muscle contraction, where force is generated without muscle shortening, is a molecular traffic jam in which the number of actin-attached motors is maximized and all states of motor action are trapped with consequently high heterogeneity. This heterogeneity is a major limitation to deciphering myosin conformational changes in situ. We used multivariate data analysis to group repeat segments in electron tomograms of isometrically contracting insect flight muscle, mechanically monitored, rapidly frozen, freeze substituted, and thin sectioned. Improved resolution reveals the helical arrangement of F-actin subunits in the thin filament enabling an atomic model to be built into the thin filament density independent of the myosin. Actin-myosin attachments can now be assigned as weak or

SUBMITTER: Wu S 

PROVIDER: S-EPMC2936580 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature