Open AccessFluorimetry Study of N ‐(1‐Pyrenyl)iodoacetamide‐Labelled F‐Actin
Author(s) -
KOUYAMA Tsutomu,
MIHASHI Koshin
Publication year - 1981
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1981.tb06167.x
Subject(s) - iodoacetamide , heavy meromyosin , chemistry , fluorescence , polymerization , actin , conjugate , photochemistry , biophysics , biochemistry , polymer , cysteine , enzyme , organic chemistry , biology , mathematical analysis , physics , mathematics , quantum mechanics
A fluorescent reagent, N ‐(1‐pyrenyl)iodoacetamide, was conjugated to rabbit skeletal muscle actin at the site of the most reactive sulfhydryl group, and fluorescence characteristics (excitation and emission spectra, quantum yields, lifetimes) of the conjugate were investigated. Associated with polymerization of labelled G‐actin, the fluorescence intensity at 407 nm, after excitation at 365 nm, was enhanced by a factor of about 25. It was reduced to about 25% on the binding of heavy meromyosin (or subfragment 1). The results suggest that binding of heavy meromyosin to the protomer of F‐actin alters the local structure of the protomer towards a G‐actin‐like one.