Synthetic peptide of the sequence 632-642 on myosin subfragment 1 inhibits actomyosin ATPase activity.
A synthetic peptide corresponding to a sequence 632-642 (S632-642) on the myosin subfragment 1 (S-1) heavy chain and spanning the 50/20 kDa junction of S-1 binds to actin in the presence and absence of S-1. The binding of 1.0 mole of peptide per actin causes almost complete inhibition of actomyosin ATPase activity and only partial inhibition of S-1 binding to actin. The binding of S632-642 to the N-terminal segment of actin is supported by competitive carbodiimide cross-linking of S-1 and S632-642 to actin and the catalytic properties of cross-linked acto-S-1 and actin-peptide complexes. These results show that the sequence 632-642 on S-1 is an autonomous binding site for actin and confirm the catalytic importance of its interactions with the N-terminal segment of actin.
Cheung
P
P
Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.
Reisler
E
E
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002234:Carbodiimides / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D007700:Kinetics; D008969:Molecular Sequence Data; D015879:Myosin Subfragments / Q000138:chemical synthesis / Q000494:pharmacology*; D009218:Myosins / Q000037:antagonists & inhibitors*; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000494:pharmacology*; D011485:Protein Binding
D000199:Actins; D002234:Carbodiimides; D003432:Cross-Linking Reagents; D015879:Myosin Subfragments; D010446:Peptide Fragments; D017301:Ca(2+) Mg(2+)-ATPase; D009218:Myosins