Differential interaction of cardiac, skeletal muscle, and yeast tropomyosins with fluorescent (pyrene235) yeast actin.

ABSTRACT: To monitor binding of tropomyosin to yeast actin, we mutated S235 to C and labeled the actin with pyrene maleimide at both C235 and the normally reactive C374. Saturating cardiac tropomyosin (cTM) caused about a 20% increase in pyrene fluorescence of the doubly labeled F-actin but no change in WT actin C374 probe fluorescence. Skeletal muscle tropomyosin caused only a 7% fluorescence increase, suggesting differential binding modes for the two tropomyosins. The increased cTM-induced fluorescence was proportional to the extent of tropomyosin binding. Yeast tropomyosin (TPM1) produced less increase in fluorescence than did cTM, whereas that caused by yeast TPM2 was greater than either TPM1 or cTM. Cardiac troponin largely reversed the cTM-induced fluorescence increase, and subsequent addition

SUBMITTER: Chen W 

PROVIDER: S-EPMC1367282 | biostudies-literature | 2006 Feb

REPOSITORIES: biostudies-literature