In:
PLOS ONE, Public Library of Science (PLoS), Vol. 18, No. 5 ( 2023-5-19), p. e0285343-
Abstract:
The flagellar motor supports bacterial chemotaxis, a process that allows bacteria to move in response to their environment. A central feature of this motor is the MS-ring, which is composed entirely of repeats of the FliF subunit. This MS-ring is critical for the assembly and stability of the flagellar switch and the entire flagellum. Despite multiple independent cryoEM structures of the MS-ring, there remains a debate about the stoichiometry and organization of the ring-building motifs (RBMs). Here, we report the cryoEM structure of a Salmonella MS-ring that was purified from the assembled flagellar switch complex (MSC-ring). We term this the ‘post-assembly’ state. Using 2D class averages, we show that under these conditions, the post-assembly MS-ring can contain 32, 33, or 34 FliF subunits, with 33 being the most common. RBM3 has a single location with C32, C33, or C34 symmetry. RBM2 is found in two locations with RBM2 inner having C21 or C22 symmetry and an RBM2 outer -RBM1 having C11 symmetry. Comparison to previously reported structures identifies several differences. Most strikingly, we find that the membrane domain forms 11 regions of discrete density at the base of the structure rather than a contiguous ring, although density could not be unambiguously interpreted. We further find density in some previously unresolved areas, and we assigned amino acids to those regions. Finally, we find differences in interdomain angles in RBM3 that affect the diameter of the ring. Together, these investigations support a model of the flagellum with structural plasticity, which may be important for flagellar assembly and function.
Type of Medium:
Online Resource
ISSN:
1932-6203
DOI:
10.1371/journal.pone.0285343
DOI:
10.1371/journal.pone.0285343.g001
DOI:
10.1371/journal.pone.0285343.g002
DOI:
10.1371/journal.pone.0285343.g003
DOI:
10.1371/journal.pone.0285343.g004
DOI:
10.1371/journal.pone.0285343.g005
DOI:
10.1371/journal.pone.0285343.g006
DOI:
10.1371/journal.pone.0285343.g007
DOI:
10.1371/journal.pone.0285343.g008
DOI:
10.1371/journal.pone.0285343.g009
DOI:
10.1371/journal.pone.0285343.t001
DOI:
10.1371/journal.pone.0285343.s001
DOI:
10.1371/journal.pone.0285343.s002
DOI:
10.1371/journal.pone.0285343.s003
DOI:
10.1371/journal.pone.0285343.s004
Language:
English
Publisher:
Public Library of Science (PLoS)
Publication Date:
2023
detail.hit.zdb_id:
2267670-3
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