The effect of myosin light chain phosphorylation and Mg2+ on the conformation of myosin in thick filaments of glycerinated fibers of rabbit skeletal muscle.
It has been shown by polarization microfluorimetry that phosphorylation of myosin light chain 2, in stretched single glycerinated fibers of rabbit skeletal muscle, results in changes in polarized fluorescence anisotropy of both the tryptophan residues of myosin molecules and the fluorescent label, N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine, associated with the fast-reacting thiol group in myosin heads. These changes are also dependent on the presence or absence of Mg2+ in the medium: they are most pronounced in the presence of 5 mM MgCl2. It is assumed that both Mg2+ binding to myosin and phosphorylation of light chain 2 associated with myosin heads induce structural changes in myosin filaments of muscle fibres which are expressed as changes in the orientation of myosin heads and in the conformation of myosin rods.
Borovikov
Y S
YS
Group of Cell Motility, Institute of Cytology, Academy of Sciences of the USSR, Leningrad.
Levitsky
D I
DI
D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D003720:Densitometry; D004591:Electrophoresis, Polyacrylamide Gel; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D005990:Glycerol; D008274:Magnesium / Q000494:pharmacology*; D009132:Muscles / Q000032:analysis* / Q000187:drug effects; D009218:Myosins / Q000378:metabolism*; D009282:Naphthalenesulfonates / Q000032:analysis; D010766:Phosphorylation; D011487:Protein Conformation; D011817:Rabbits; D014364:Tryptophan / Q000032:analysis
D005456:Fluorescent Dyes; D009282:Naphthalenesulfonates; C006421:1,5-I-AEDANS; D014364:Tryptophan; D009218:Myosins; D008274:Magnesium; D005990:Glycerol