期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1990
卷号：87
期号：6
页码：2284-2288
DOI：10.1073/pnas.87.6.2284
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The amino acid sequence for chicken smooth muscle myosin light chain kinase (smMLCK) was deduced from a full-length cDNA. This has allowed definition of both the complete sequence of the inactive 64-kDa proteolytic fragment, which contains the pseudosubstrate autoregulatory sequence, and of the active 61-kDa Ca2+/calmodulin-independent fragment, which lacks the autoregulatory domain. Comparison of the two sequences shows that the autoregulatory domain extends from Asn-780 to Arg-808. The peptide Leu-774 to Ser-787 does not inhibit smMLCK, whereas peptides of similar or shorter length from the pseudosubstrate region (Ser-787 to Val-807) are potent inhibitors. These data define the autoregulatory region as being contained within and probably identical to the pseudosubstrate domain. The catalytic and regulatory regions are flanked by several copies of 100-amino acid segments containing one of two consensus motifs. These motifs are absent from mammalian skeletal muscle MLCK or from Dictyostelium discoideum MLCK but are present in the Caenorhabditis elegans unc-22 gene product and the titin molecule of skeletal muscle myofibrils. These results indicate that the amino acid sequence of smMLCK encodes multiple functional motifs in addition to the catalytic domain.
