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Structural heterogeneity of carbohydrate modifications affects serospecificity of Campylobacter flagellins
Author(s) -
Logan Susan M.,
Kelly John F.,
Thibault Pierre,
Ewing Cheryl P.,
Guerry Patricia
Publication year - 2002
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2002.03185.x
Subject(s) - flagellin , campylobacter jejuni , biology , mutant , complementation , escherichia coli , gene , biochemistry , amino acid , campylobacter , isoelectric focusing , antiserum , microbiology and biotechnology , bacteria , genetics , antibody , enzyme
Summary Flagellin from Campylobacter coli VC167 is post‐translationally modified at ≥ 16 amino acid residues with pseudaminic acid and three related derivatives. The predominant modification was 5,7‐diacetamido‐3,5,7,9 ‐ tetradeoxy ‐ l ‐ glycero ‐ l ‐ manno ‐ nonulosonic acid (pseudaminic acid, Pse5Ac7Ac), a modification that has been described previously on flagellin from Campylobacter jejuni 81‐176. VC167 lacked two modi‐fications present in 81‐176 and instead had two unique modifications of masses 431 and 432 Da. Flagellins from both C. jejuni 81‐176 and C. coli VC167 were also modified with an acetamidino form of pseudaminic acid (PseAm), but tandem mass spectrometry indicated that the structure of PseAm differed in the two strains. Synthesis of PseAm in C. coli VC167 requires a minimum of six ptm genes. In contrast, PseAm is synthesized in C. jejuni 81‐176 via an alternative pathway using the product of the pseA gene. Mutation of the ptm genes in C. coli VC167 can be detected by changes in apparent M r of flagellin in SDS‐PAGE gels, changes in isoelectric focusing (IEF) patterns and loss of immunoreactivity with antiserum LAH2. These changes corresponded to loss of both 315 Da and 431 Da modifications from flagellin. ComplementationoftheVC167ptmmutantswiththe 81‐176 pseA gene in trans resulted in flagellins containing both 315 and 431 Da modifications, but these flagellins remained unreactive in LAH2 antibody, suggesting that the unique form of PseAm encoded by the ptm genes contributes to the serospecificity of the flagellar filament.