A chimeric N-terminal Escherichia coli--C-terminal Rhodobacter sphaeroides FliG rotor protein supports bidirectional E. coli flagellar rotation and chemotaxis.
Flagellate bacteria such as Escherichia coli and Salmonella enterica serovar Typhimurium typically express 5 to 12 flagellar filaments over their cell surface that rotate in clockwise (CW) and counterclockwise directions. These bacteria modulate their swimming direction towards favorable environments by biasing the direction of flagellar rotation in response to various stimuli. In contrast, Rhodobacter sphaeroides expresses a single subpolar flagellum that rotates only CW and responds tactically by a series of biased stops and starts. Rotor protein FliG transiently links the MotAB stators to the rotor, to power rotation and also has an essential function in flagellar export. In this study, we sought to determine whether the FliG protein confers directionality on flagellar motors by testing the functional properties of R. sphaeroides FliG and a chimeric FliG protein, EcRsFliG (N-terminal and central domains of E. coli FliG fused to an R. sphaeroides FliG C terminus), in an E. coli FliG null background. The EcRsFliG chimera supported flagellar synthesis and bidirectional rotation; bacteria swam and tumbled in a manner qualitatively similar to that of the wild type and showed chemotaxis to amino acids. Thus, the FliG C terminus alone does not confer the unidirectional stop-start character of the R. sphaeroides flagellar motor, and its conformation continues to support tactic, switch-protein interactions in a bidirectional motor, despite its evolutionary history in a bacterium with a unidirectional motor.
Morehouse
Karen A
KA
Institute of Genetics, School of Biology, University of Nottingham, Medical School, QMC, Nottingham NG7 2UH, United Kingdom.
Goodfellow
Ian G
IG
Sockett
R Elizabeth
RE
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D002633:Chemotaxis / Q000502:physiology; D017124:Conserved Sequence; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D005407:Flagella / Q000737:chemistry / Q000502:physiology*; D015870:Gene Expression; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000502:physiology; D012242:Rhodobacter sphaeroides / Q000235:genetics / Q000502:physiology*; D012399:Rotation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; C075660:Flig protein, Bacteria; D011993:Recombinant Fusion Proteins
J Bacteriol. 2000 Jun;182(11):3022-8
10809678
FEMS Microbiol Lett. 1996 Aug 15;142(1):111-6
8759796
J Bacteriol. 2000 Sep;182(18):5218-24
10960108
J Bacteriol. 2001 Nov;183(21):6404-12
11591685
J Mol Biol. 1997 Mar 7;266(4):733-44
9102466
J Bacteriol. 1998 May;180(10):2729-35
9573160
Proc Natl Acad Sci U S A. 1998 May 26;95(11):6436-41
9600984
Nature. 1999 Jul 29;400(6743):472-5
10440379
J Gen Microbiol. 1962 Sep;28:607-16
13913485
Annu Rev Biochem. 2003;72:19-54
12500982
Biochemistry. 2001 Oct 30;40(43):13041-50
11669642
EMBO J. 2002 Jul 1;21(13):3225-34
12093724
FEBS Lett. 2003 Jun 12;545(1):86-95
12788496
Biophys J. 2003 Aug;85(2):843-52
12885632
Annu Rev Microbiol. 2003;57:77-100
12730325
J Mol Biol. 2003 Nov 28;334(3):567-83
14623195
J Bacteriol. 1967 Jan;93(1):390-8
5335897
Gene. 1982 Oct;19(3):259-68
6295879
J Bacteriol. 1985 Mar;161(3):955-62
2982796
Gene. 1985;33(1):103-19
2985470
J Bacteriol. 1987 Feb;169(2):514-8
3492489
J Bacteriol. 1988 Jan;170(1):320-9
3257209
J Bacteriol. 1988 Oct;170(10):4509-15
3049535
Gene. 1988 Oct 15;70(1):191-7
2853689
Nucleic Acids Res. 1989 May 11;17(9):3469-78
2657660
Nature. 1991 Feb 14;349(6310):630-3
2000137
J Bacteriol. 1992 Apr;174(7):2298-304
1551848
J Bacteriol. 1993 Feb;175(3):802-10
8423152
J Bacteriol. 1996 Jan;178(1):223-31
8550421
J Mol Biol. 1996 Mar 1;256(3):564-76
8604139
J Mol Biol. 1996 May 3;258(2):270-85
8627625
J Bacteriol. 2000 Aug;182(15):4234-40
10894732