Acidic residues comprise part of the myosin light chain-binding site on skeletal muscle myosin light chain kinase

B. Herring, Daniel P. Fitzsimons, James T. Stull, Patricia Gallagher

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Myosin light chain kinase is a Ca2+/calmodulin-dependent protein kinase which exhibits a very high degree of protein substrate specificity. The regulatory light chain of myosin is the only known physiological substrate of the enzyme. Based upon epitope mapping of monoclonal antibodies which inhibit kinase activity competitively with respect to the light chain substrate, residues 235-319 of the rabbit skeletal muscle kinase have been proposed to contain a light chain-binding site (Herring, B. P., Stull, J. T., and Gallagher, P. J. (1990) J. Biol. Chem. 265, 1724-1730). With the expression of a truncated kinase, we have further localized this putative binding site to residues 235-294. Mutation of acidic residues at positions 269 and 270 of the kinase resulted in a 10-fold increase in the Km value for the myosin light chain, with no significant change in the Vmax value. In contrast, altering a cluster of acidic amino acids at positions 261-263 had little effect on the Km value for the myosin light chain. These results suggest that residues 269 and 270 may be involved in protein-substrate binding. Interestingly, these residues, located amino-terminal of the homologous catalytic core (positions 302-539), are in a region which is highly conserved among myosin light chain kinases, but not other protein kinases. It is probable that the homologous catalytic core contains structural elements required for phosphotransferase activity. The catalytic domain of myosin light chain kinase would therefore include these conserved elements together with additional specific substrate-binding residues.

Original languageEnglish (US)
Pages (from-to)16588-16591
Number of pages4
JournalJournal of Biological Chemistry
Volume265
Issue number27
StatePublished - Sep 25 1990
Externally publishedYes

Fingerprint

Skeletal Muscle Myosins
Myosin-Light-Chain Kinase
Myosin Light Chains
Phosphotransferases
Binding Sites
Substrates
Catalytic Domain
Acidic Amino Acids
Epitope Mapping
Light
Calcium-Calmodulin-Dependent Protein Kinases
Substrate Specificity
Protein Binding
Protein Kinases
Muscle
Epitopes
Skeletal Muscle
Proteins
Monoclonal Antibodies
Rabbits

ASJC Scopus subject areas

  • Biochemistry

Cite this

Herring, B., Fitzsimons, D. P., Stull, J. T., & Gallagher, P. (1990). Acidic residues comprise part of the myosin light chain-binding site on skeletal muscle myosin light chain kinase. Journal of Biological Chemistry, 265(27), 16588-16591.

Acidic residues comprise part of the myosin light chain-binding site on skeletal muscle myosin light chain kinase. / Herring, B.; Fitzsimons, Daniel P.; Stull, James T.; Gallagher, Patricia.

In: Journal of Biological Chemistry, Vol. 265, No. 27, 25.09.1990, p. 16588-16591.

Research output: Contribution to journalArticle

Herring, B, Fitzsimons, DP, Stull, JT & Gallagher, P 1990, 'Acidic residues comprise part of the myosin light chain-binding site on skeletal muscle myosin light chain kinase', Journal of Biological Chemistry, vol. 265, no. 27, pp. 16588-16591.
Herring, B. ; Fitzsimons, Daniel P. ; Stull, James T. ; Gallagher, Patricia. / Acidic residues comprise part of the myosin light chain-binding site on skeletal muscle myosin light chain kinase. In: Journal of Biological Chemistry. 1990 ; Vol. 265, No. 27. pp. 16588-16591.
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