Molecular characterization of motility genes in Bacillus subtilis

The synthesis of the bacterial flagellum is a complex process requiring up to fifty gene products in organisms such as Escherichia coli and Bacillus subtilis. Several genes involved in the process of flagellar synthesis have been identified and characterized from the che/fla operon of B. subtilis, a 26 kilobase (kb) transcription unit. One B. subtilis gene, designated as flhF, was found to encode for a putative GTP-binding protein that displayed sequence similarities to components of the eukaryotic secretory apparatus. Subsequent biochemical analysis demonstrated that FlhF can bind to GTP and GDP, but not to ATP. FlhF is the first GTP-binding flagellar protein to be described in any organism, including the well-studied bacterium, E. coli. These results suggest that a guanosine nucleotide-dependent signalling mechanism is required, in some capacity, to generate a B. subtilis flagellum. A further analysis of the che/fla operon uncovered flhA, a flagellar gene that encodes for a putative signal-transducing receptor as suggested through strong amino acid homologies to a variety of proteins. Based upon some genetic and biochemical information, the hypothesis has been put forward that FlhA and FlhF interact to form the basis of a GTP-dependent signalling pathway. Because of this and previous information, we suggest a scenario whereby FlhA and FlhF cooperate to function during B. subtilis flagellar morphogenesis. Lastly, this work documents, as other researchers have, that some proteins required for the synthesis of the flagellum are related to proteins essential for the export of virulence proteins in a wide variety of pathogenic organisms. These observations reinforce the notion that a superfamily of proteins exists to govern the process of assembling supramolecular structures that lie in and outside of the bacterial cell membrane.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biology, Molecular

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Carpenter, Phillip Brian

Contributors dc:contributor

• Ordal, George W.

• Biology, Molecular
• Biology, Microbiology

Statement dc:rights

• Copyright 1994 Carpenter, Phillip Brian

Language dc:language

eng

Identifier

AAI9416342
(UMI)AAI9416342

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/23554