Overproduction of the bacterial flagellar switch proteins and their interactions with the MS ring complex in vitro.
The flagellar switch proteins (FliG, FliM, and FliN) of Salmonella typhimurium were overproduced in Escherichia coli and partially purified in soluble form. They were mixed with purified MS ring complexes (which consist of subunits of FliF protein) to examine their interactions in vitro. The degree of interaction was estimated by ultracentrifugation, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. From the band density on the gel, we estimated that FliG bound to the MS ring complex at an approximately 1:1 molar ratio (FliG:FliF), whereas FliM did so only at a 1:5 molar ratio (FliM:FliF). FliN did not bind to the MS ring complex by itself or in the presence of the other switch proteins. A possible configuration of the switch proteins is discussed.
Oosawa
K
K
Department of Biosciences, School of Science and Engineering, Teikyo University, Utsunomiya, Japan.
Ueno
T
T
Aizawa
S
S
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D005407:Flagella / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000096:biosynthesis; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; C077389:FliN protein, Bacteria; C075660:Flig protein, Bacteria; D011994:Recombinant Proteins; C066821:FliM protein, Bacteria