Absorption, Fluorescence, and Linear Dichroism Spectra of Fluorescein Mercuric Acetate (FMA) bound to F-actin
- 1 February 1979
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journal of Biochemistry
- Vol. 85 (2) , 359-366
- https://doi.org/10.1093/oxfordjournals.jbchem.a132341
Abstract
Two kinds of F-actin were prepared; one binds magnesium at the unique divalent cation binding site of actin protomer and the other binds calcium at this site. They were designated as F(Mg)-actin and F(Ca)-actin, respectively. The binding of fluorescein mercuric acetate (FMA) to F(Mg)-actin and F(Ca)-actin was studied spectroscopically. The absorption and fluorescence spectra of bound FMA differed slightly but distinctly between F(Mg)-actin and F(Ca)-actin. Moreover, FMA bound to F(Mg)-actin showed linear dichroism in the presence of 2 m MgCl2 (or 2 mM CaCl2 in the solvent, while the dichroism was abolished by the removal of divalent cations from the solvent, in contrast, FMA bound to F(Ca)-actin did not show any appreciable linear dichroism irrespective of the presence (or absence) of divalent cations in the solvent. These results suggest that the structure of F-actin is characteristically regulated by divalent cations in a dual mode.This publication has 1 reference indexed in Scilit:
- An assay method for disulfide groups by fluorescence quenchingAnalytical Biochemistry, 1964