Phosphorylatable serine residues are located in a non-helical tailpiece of a catch muscle myosin.
Myosin from a molluscan catch muscle displays unusual properties: when phosphorylated in the rod by an endogenous heavy-chain kinase, myosin solubility is enhanced and the molecule folds (Castellani & Cohen, Proc. natn. Acad. Sci. U.S.A. 84, (1987) 4058-62). We have now localized the sites of phosphorylation to the carboxy-terminal end of the rod by selective proteolytic cleavage. Two major stretches of sequence, 18 and 21 residues long, have been identified, each containing a single residue of phosphoserine. Analysis of the amino-acid sequence of these two peptides indicates that they form a non-helical tailpiece. We discuss how phosphorylation of this tailpiece might influence enzymatic activity in catch muscle thick filaments.
Castellani
L
L
Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02254.
Elliott
B W
BW
Cohen
C
C
D000595:Amino Acid Sequence; D000818:Animals; D002918:Chymotrypsin / Q000494:pharmacology; D008969:Molecular Sequence Data; D008974:Mollusca / Q000032:analysis*; D009132:Muscles / Q000032:analysis* / Q000187:drug effects / Q000502:physiology; D009218:Myosins / Q000032:analysis*; D010768:Phosphoserine / Q000032:analysis*; D012694:Serine / Q000031:analogs & derivatives*
D010768:Phosphoserine; D012694:Serine; D002918:Chymotrypsin; D009218:Myosins