Regulated underexpression of the FliM protein of Escherichia coli and evidence for a location in the flagellar motor distinct from the MotA/MotB torque generators.

摘要: The FliM protein of Escherichia coli is essential for the assembly and function flagella. Here, we report effects controlled low-level expression in a fliM null strain. Disruption gene abolishes flagellation. Underexpression causes cells to produce comparatively few flagella, most flagella built are defective, producing subnormal average torque fluctuating rapidly speed. results imply that normal flagellar motor, multiple molecules present can independently some degree. speed fluctuations indicate stable operation requires most, possibly all, complement FliM. Thus, subunits not as fully independent motility proteins MotA MotB characterized earlier work, suggesting occupies location motor distinct from MotA/MotB generators. Several mutations previously reported cause paralysis Salmonella typhimurium (H. Sockett, S. Yamaguchi, M. Kihara, V.M. Irikura, R. Macnab, J. Bacteriol. 174:793-806, 1992) were made E. coli. These did coli; their phenotypes more complex suggest directly involved generation.