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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
14
pubmed:dateCreated
1991-5-13
pubmed:abstractText
Site-directed mutagenesis of smooth muscle myosin light chain kinase was applied to define its autoinhibitory domain. Mutants were all initiated at Leu-447 but contained varying lengths of C-terminal sequence. Those containing the complete C-terminal sequence to Glu-972 possessed kinase activities that were calmodulin-dependent. Removal of the putative inhibitory domain by truncation to Thr-778 resulted in generation of a constitutively active (calmodulin-independent) species. Thus, the inhibitory domain lies to the C-terminal side of Thr-778. Truncation to Lys-793 and to Trp-800 also resulted in constitutively active mutants, although the specific activity of the latter was less than the other mutants. None of the truncated mutants bound calmodulin. For each mutant, the Km values with respect to ATP and to the 20,000-dalton light chain were similar to values obtained with the native enzyme. The presence of the inhibitory domain was detected by activation of kinase activity following limited proteolysis with trypsin. Using this procedure, it was determined that the inhibitory domain was manifest only in the mutant truncated to Trp-800 and was absent from that ending at Lys-793. These results indicate that a critical region of the inhibitory domain is contained within the sequence Tyr-794 to Trp-800. This region overlaps with the calmodulin-binding site for five residues. Our assignment of the inhibitory sequence is consistent with autoinhibition via a pseudosubstrate domain.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3498-503
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Definition of the inhibitory domain of smooth muscle myosin light chain kinase by site-directed mutagenesis.
pubmed:affiliation
First Medical Clinic, Mie University Hospital, Mieken, Japan.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.