title: Actin-binding peptide from smooth muscle myosin light chain kinase.
abstract: The objective of this study was to localize the actin-binding site in the smooth muscle myosin light chain kinase. Limited proteolysis by thermolysin indicated that hydrolysis of the kinase at the N-terminal end of the molecule resulted in loss of actin-binding ability. Various methods of cleavage were investigated for the generation of a discrete actin-binding peptide. The method chosen was cleavage at the cysteine residues by the 5,5'-dithiobis(2-nitrobenzoic acid)-cyanide complex. This procedure yielded an actin-binding peptide of approximate M(r) 17,000. The peptide was purified and shown to possess the actin-binding properties of the native myosin light chain kinase. The binding constant of the isolated peptide and parent enzyme to actin was estimated as 7.5 x 10(4) M-1. From the amino acid composition of the peptide and comparison with the sequence of gizzard myosin light chain kinase, it was suggested that the actin-binding site is located within the N-terminal sequence 1-114. Comparison with other actin-binding proteins shows some similarities to gizzard alpha-actinin and caldesmon.
authors.affiliation: Faculty of Bioresources, Mie University, Tsu, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kanoh
authors.forename: M
authors.initials: M
authors.lastname: Ito
authors.forename: E
authors.initials: E
authors.lastname: Niwa
authors.forename: Y
authors.initials: Y
authors.lastname: Kawano
authors.forename: D J
authors.initials: DJ
authors.lastname: Hartshorne
mesh_terms: D000199:Actins / Q000378:metabolism*; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D002645:Chickens; D004591:Electrophoresis, Polyacrylamide Gel; D006041:Goats; D006868:Hydrolysis; D009130:Muscle, Smooth / Q000201:enzymology*; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D014422:Turkeys
chemical_list: D000199:Actins; D000596:Amino Acids; D010446:Peptide Fragments; D009219:Myosin-Light-Chain Kinase