MULTIPLE ELECTROPHORETIC FORMS OF METHYL-ACCEPTING CHEMOTAXIS PROTEINS GENERATED BY STIMULUS-ELICITED METHYLATION IN ESCHERICHIA-COLI
MULTIPLE ELECTROPHORETIC FORMS OF METHYL-ACCEPTING CHEMOTAXIS PROTEINS GENERATED BY STIMULUS-ELICITED METHYLATION IN ESCHERICHIA-COLI
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DOI：
10.1128/jb.143.2.809-815.1980
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发表时间：
1980-01-01
影响因子：
3.2
通讯作者：
SIMON, MI
中科院分区：
文献类型：
--
作者：
BOYD, A;SIMON, MI
The tsr and tar genetic loci of E. coli determine the presence in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of methyl-accepting chemotaxis proteins (MCP) I and II, respectively, each of which consists of a distinct group of multiple bands. Synthesis of the tsr and tar products was directed in UV-irradiated bacteria by .lambda. transducing phages. The addition of appropriate chemotactic stimuli to these cells resulted in the appearance of additional, faster migrating electrophoretic forms of the Tsr and Tar polypeptides, which disappeared upon removal of the stimulus. The stimulus-elicited forms comigrated with component bands of the corresponding MCP. Apparently methylation itself caused shifts in electrophoretic mobility and hence led to the observed MCP band patterns. The number of Tsr species suggested that there were at least 3 methylated sites on the Tsr polypeptide. The conclusion that methylation generates multiplicity was supported by the results of experiments in which the tsr product was synthesized in mutant bacteria defective in specific chemotaxis functions concerned with methylation or demethylation of MCP. Thus, the presence of a cheX defect blocked the stimulus-elicited appearance of faster migrating forms of the tsr product; conversely, the presence of a cheB defect resulted in a pronounced shift toward these forms in the absence of a chemotactic stimulus.
