REGULATORY AND STRUCTURAL MOTIFS OF CHICKEN GIZZARD MYOSIN LIGHT CHAIN KINASE
REGULATORY AND STRUCTURAL MOTIFS OF CHICKEN GIZZARD MYOSIN LIGHT CHAIN KINASE
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DOI：
10.1073/pnas.87.6.2284
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发表时间：
1990-03-01
影响因子：
11.1
通讯作者：
MEANS, AR
中科院分区：
文献类型：
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作者：
OLSON, NJ;PEARSON, RB;MEANS, AR
鸡肌球蛋白轻链激酶(SmMLCK)的氨基酸序列是从一个全长的cDNA中推导出来的。这使得对无活性的-kDa蛋白水解性片段的完整序列和活性的61 kDa钙/钙调素非依赖性片段的定义成为可能，前者包含假底物自身调节序列，后者缺乏自身调节域。两个序列的比较表明，其自身调节结构域从ASN-780延伸到Arg-808。Leu-774到Ser-787不抑制smMLCK，而来自假底物区域的类似或更短长度的多肽(Ser-787到Val-807)是有效的抑制剂。这些数据将自身调节区定义为包含在伪底物结构域中并可能与其相同。催化和调节区两侧是几个拷贝的100个氨基酸片段，包含两个共同的基序之一。这些基序在哺乳动物骨骼肌MLCK和盘基网眼藻MLCK中不存在，但在秀丽线虫UNC-22基因产物和骨骼肌肌原纤维的Titin分子中存在。这些结果表明，smMLCK的氨基酸序列除了催化结构域外，还编码多种功能基序。
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.