Open AccessFlagellin lysine methyltransferase FliB catalyzes a [4Fe-4S] mediated methyl transfer reaction
Author(s) -
Chu Wang,
Christian Nehls,
Dirk Baabe,
Olaf Burghaus,
Robert Hurwitz,
Thomas Gutsmann,
Martin Bröring,
Michael Kolbe
Publication year - 2021
Publication title -
plos pathogens
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.719
H-Index - 206
eISSN - 1553-7374
pISSN - 1553-7366
DOI - 10.1371/journal.ppat.1010052
Subject(s) - flagellin , methylation , methyltransferase , chemistry , biochemistry , lysine , salmonella enterica , electron paramagnetic resonance , amino acid , escherichia coli , gene , physics , nuclear magnetic resonance
The methyltransferase FliB posttranslationally modifies surface-exposed ɛ-N-lysine residues of flagellin, the protomer of the flagellar filament in Salmonella enterica (S . enterica) . Flagellin methylation, reported originally in 1959, was recently shown to enhance host cell adhesion and invasion by increasing the flagellar hydrophobicity. The role of FliB in this process, however, remained enigmatic. In this study, we investigated the properties and mechanisms of FliB from S . enterica in vivo and in vitro . We show that FliB is an S-adenosylmethionine (SAM) dependent methyltransferase, forming a membrane associated oligomer that modifies flagellin in the bacterial cytosol. Using X-band electron paramagnetic resonance (EPR) spectroscopy, zero-field 57 Fe Mössbauer spectroscopy, methylation assays and chromatography coupled mass spectrometry (MS) analysis, we further found that FliB contains an oxygen sensitive [4Fe-4S] cluster that is essential for the methyl transfer reaction and might mediate a radical mechanism. Our data indicate that the [4Fe-4S] cluster is coordinated by a cysteine rich motif in FliB that is highly conserved among multiple genera of the Enterobacteriaceae family.