Parker, J.L., Day-Williams, M.J., Tomas, J.M. et al. (2 more authors) (2012) Identification of a putative glycosyltransferase responsible for the transfer of pseudaminic acid onto the polar flagellin of Aeromonas caviae Sch3N. Microbiology Open, 1 (2). 149 - 160. ISSN 2045-8827
Abstract
Motility in Aeromonas caviae, in a liquid environment (in broth culture), is mediated by a single polar flagellum encoded by the fla genes. The polar flagellum filament of A. caviae is composed of two flagellin subunits, FlaA and FlaB, which undergo O-linked glycosylation with six to eight pseudaminic acid glycans linked to serine and threonine residues in their central region. The flm genetic locus in A. caviae is required for flagellin glycosylation and the addition of pseudaminic acid (Pse) onto the lipopolysaccharide (LPS) O-antigen. However, none of the flm genes appear to encode a candidate glycotransferase that might add the Pse moiety to FlaA/B. The motility-associated factors (Maf proteins) are considered as candidate transferase enzymes, largely due to their conserved proximity to flagellar biosynthesis loci in a number of pathogens. Bioinformatic analysis performed in this study indicated that the genome of A. caviae encodes a single maf gene homologue (maf1). A maf mutant was generated and phenotypic analysis showed it is both nonmotile and lacks polar flagella. In contrast to flm mutants, it had no effect on the LPS O-antigen pattern and has the ability to swarm. Analysis of flaA transcription by reverse transcriptase PCR (RT-PCR) showed that its transcription was unaltered in the maf mutant while a His-tagged version of the FlaA flagellin protein produced from a plasmid was detected in an unglycosylated intracellular form in the maf strain. Complementation of the maf strain in trans partially restored motility, but increased levels of glycosylated flagellin to above wild-type levels. Overexpression of maf inhibited motility, indicating a dominant negative effect, possibly caused by high amounts of glycosylated flagellin inhibiting assembly of the flagellum. These data provide evidence that maf1, a pseudaminyl transferase, is responsible for glycosylation of flagellin and suggest that this event occurs prior to secretion through the flagellar Type III secretion system.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2012 The Authors. MicrobiologyOpen published by Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. |
Keywords: | Aeromonas; motility; flagella |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Chemical and Biological Engineering (Sheffield) The University of Sheffield > Sheffield Teaching Hospitals The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > Department of Infection and Immunity (Sheffield) The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > School of Clinical Dentistry (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 01 Dec 2015 15:05 |
Last Modified: | 18 Nov 2016 17:10 |
Published Version: | http://dx.doi.org/10.1002/mbo3.19 |
Status: | Published |
Publisher: | Wiley Open Access |
Refereed: | Yes |
Identification Number: | 10.1002/mbo3.19 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:90056 |