Affiliation:
1. Departamento de Genética Molecular, Instituto de Fisiologı́a Celular,1 and
2. Departamento de Biologı́a Molecular, Instituto de Investigaciones Biomédicas,2 UNAM, 04510 México D.F., México
Abstract
ABSTRACT
In this work we identified the
flgE
gene encoding the flagellar hook protein from
Rhodobacter sphaeroides
. Our results show that this gene is part of a flagellar cluster that includes the genes
flgB, flgC, flgD, flgE
, and
flgF
. Two different types of mutants in the
flgE
gene were isolated, and both showed a Fla
−
phenotype, indicating the functionality of this sequence. Complementation studies of these mutant strains suggest that
flgE
is included in a single transcriptional unit that starts in
flgB
and ends in
flgF
. In agreement with this possibility, a specific transcript of approximately 3.5 kb was identified by Northern blot. This mRNA is large enough to represent the complete
flgBCDEF
operon. FlgE showed a relatively high proline content; in particular, a region of 12 amino acids near the N terminus, in which four prolines were identified. Cells expressing a mutant FlgE protein lacking this region showed abnormal swimming behavior, and their hooks were curved. These results suggest that this region is involved in the characteristic quaternary structure of the hook of
R. sphaeroides
and also imply that a straight hook, or perhaps the rigidity associated with this feature, is important for an efficient swimming behavior in this bacterium.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
17 articles.
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