Fast x-ray recordings reveal dynamic action of contractile and regulatory proteins in stretch-activated insect flight muscle.

ABSTRACT: To assess the ability of the thin-filament regulatory system to control each stretch-activation (SA) event in the fast beating of asynchronous insect flight muscle (IFM), we obtained fast (3.4 ms/frame) and semistatic (> or = 50 ms) x-ray diffraction recordings for IFM fibers from bumblebees (beating at 170 Hz) and compared the results with those acquired in giant waterbugs (20-30 Hz) and crane flies (40 Hz, semistatic only). In contrast to the well-documented large SA force of waterbug IFMs, the SA force of bumblebee and crane fly IFMs was small compared to their large isometric force. In semistatic recordings, step-stretched bumblebee and crane fly IFMs showed smaller net SA-associated intensity changes in reflections that report myosin attachment to actin and tropomyosin movement toward

SUBMITTER: Iwamoto H 

PROVIDER: S-EPMC2895363 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature