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Updated: Jun 28, 2026

Generation of Null Mutants to Elucidate the Role of Bacterial Glycosyltransferases in Bacterial Motility
Published on: March 11, 2022
A functional Campylobacter jejuni maf4 gene results in novel glycoforms on flagellin and altered autoagglutination
Lieke B van Alphen1, Manfred Wuhrer2, Nancy M C Bleumink-Pluym1
1Department of Infectious Diseases and Immunology, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
Abstract:
Flagellin of Campylobacter jejuni is extensively modified with (derivatives of) pseudaminic acid. The flagellar glycosylation locus contains several genes with homopolymeric G-tracts prone to slipped-strand mispairing, some of which belong to the maf gene family. We investigated the function of the putative phase-variable maf4 gene of C. jejuni strain 108. A constructed maf4 mutant displayed unaltered flagella assembly and bacterial motility. 2D-PAGE analysis revealed that the flagellin of strain 108 migrated at a more acidic pI than the protein of the Maf4 mutant. MS-MS in combination with high-resolution matrix-assisted laser desorption/ionization Fourier transform ion cyclotron MS (MALDI-FT-ICR-MS) on flagellin-derived glycopeptides showed that the flagellins of the mutant lacked two previously unidentified modifications of pseudaminic acid. These glycoforms carried additional CO(2) and C(2)H(2)O(2) groups, consistent with the more acidic pI of the wild-type flagellin. Phenotypically, the maf4 mutant displayed strongly delayed bacterial autoagglutination. Collectively, our results suggest that the presence of a functional Maf4 expands the flagellin glycan repertoire with novel glycoforms of pseudaminic acid and, in the event of phase variation, alters the population behaviour of C. jejuni.
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