scholarly journals Crystallization and preliminary X-ray analysis ofSalmonellaFliI, the ATPase component of the type III flagellar protein-export apparatus

Author(s):  
Tohru Minamino ◽  
Katsumi Imada ◽  
Aiko Tahara ◽  
May Kihara ◽  
Robert M. Macnab ◽  
...  
2016 ◽  
Vol 12 (3) ◽  
pp. e1005495 ◽  
Author(s):  
Tohru Minamino ◽  
Yusuke V. Morimoto ◽  
Noritaka Hara ◽  
Phillip D. Aldridge ◽  
Keiichi Namba

2003 ◽  
Vol 185 (13) ◽  
pp. 3983-3988 ◽  
Author(s):  
Tohru Minamino ◽  
Bertha González-Pedrajo ◽  
May Kihara ◽  
Keiichi Namba ◽  
Robert M. Macnab

ABSTRACT Salmonella FliI is the ATPase that drives flagellar protein export. It normally exists as a complex together with the regulatory protein FliH. A fliH null mutant was slightly motile, with overproduction of FliI resulting in substantial improvement of its motility. Mutations in the cytoplasmic domains of FlhA and FlhB, which are integral membrane components of the type III flagellar export apparatus, also resulted in substantially improved motility, even at normal FliI levels. Thus, FliH, though undoubtedly important, is not essential.


2008 ◽  
Vol 64 (a1) ◽  
pp. C236-C236
Author(s):  
T. Ibuki ◽  
M. Shimada ◽  
M. Tohru ◽  
I. Katsumi ◽  
N. Keiichi

2019 ◽  
Vol 202 (3) ◽  
Author(s):  
Tohru Minamino ◽  
Yumi Inoue ◽  
Miki Kinoshita ◽  
Keiichi Namba

ABSTRACT FlhA and FlhB are transmembrane proteins of the flagellar type III protein export apparatus, and their C-terminal cytoplasmic domains (FlhAC and FlhBC) coordinate flagellar protein export with assembly. FlhBC undergoes autocleavage between Asn-269 and Pro-270 in a well-conserved NPTH loop located between FlhBCN and FlhBCC polypeptides and interacts with the C-terminal domain of the FliK ruler when the length of the hook has reached about 55 nm in Salmonella. As a result, the flagellar protein export apparatus switches its substrate specificity, thereby terminating hook assembly and initiating filament assembly. The mechanism of export switching remains unclear. Here, we report the role of FlhBC cleavage in the switching mechanism. Photo-cross-linking experiments revealed that the flhB(N269A) and flhB(P270A) mutations did not affect the binding affinity of FlhBC for FliK. Genetic analysis of the flhB(P270A) mutant revealed that the P270A mutation affects a FliK-dependent conformational change of FlhBC, thereby inhibiting the substrate specificity switching. The flhA(A489E) mutation in FlhAC suppressed the flhB(P270A) mutation, suggesting that an interaction between FlhBC and FlhAC is critical for the export switching. We propose that the interaction between FliKC and a cleaved form of FlhBC promotes a conformational change in FlhBC responsible for the termination of hook-type protein export and a structural remodeling of the FlhAC ring responsible for the initiation of filament-type protein export. IMPORTANCE The flagellar type III protein export apparatus coordinates protein export with assembly, which allows the flagellum to be efficiently built at the cell surface. Hook completion is an important morphological checkpoint for the sequential flagellar assembly process. The protein export apparatus switches its substrate specificity from the hook protein to the filament protein upon hook completion. FliK, FlhB, and FlhA are involved in the export-switching process, but the mechanism remains a mystery. By analyzing a slow-cleaving flhB(P270A) mutant, we provide evidence that an interaction between FliK and FlhB induces conformational rearrangements in FlhB, followed by a structural remodeling of the FlhA ring structure that terminates hook assembly and initiates filament formation.


2002 ◽  
Vol 45 (4) ◽  
pp. 967-982 ◽  
Author(s):  
Bertha Gonzalez-Pedrajo ◽  
Gillian M. Fraser ◽  
Tohru Minamino ◽  
Robert M. Macnab

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