Fig. 5: Bioinformatic and functional analysis of FimT orthologues.
From: The molecular basis of FimT-mediated DNA uptake during bacterial natural transformation
a EMSA showing in vitro DNA binding of purified FimT and FimU orthologues from L. pneumophila, P. aeruginosa and X. campestris. A 30 bp dsDNA fragment (1 μM) was incubated with increasing concentrations of purified pilins (0–100 μM) and resolved by agarose gel electrophoresis. These experiments were independently performed three times with reproducible results. b A comparison of natural transformation efficiencies of the Lp02 ΔfimT strain complemented by ectopic expression of FimTLp, FimT orthologues from P. aeruginosa (FimTPa) and X. campestris (FimTXc), or chimeric FimT mutants (1–2). The corresponding composition of these FimT chimeras (1–2) is explained by a schematic drawing (top). The mean transformation efficiencies of three independent biological replicates are shown with error bars representing the SD. < d.l., below detection limit (d.l.) (average d.l. = 4.8 × 10−8 ± 2.1 × 10−8). An unpaired two-sided t-test with Welch’s correction, using log-transformed data, was used to analyse statistical significance. The Lp02 ΔfimT strain complemented with the chimeric construct was compared to the Lp02 ΔfimT strain complemented with wild-type FimT, which was in turn compared to the parental strain. n.s., not statistically significant, p > 0.05 (pfimTLp = 0.69; p1 = 0.1). c Phylogenetic tree of FimT homologues, comprising eight orders of γ-Proteobacteria illustrated by the coloured circumferential ring. Branches coloured in orange represent FimTs encoded as orphan genes, whereas those coloured red represent FimTs encoded within minor pilin operons. The positions of the four functionally characterised FimT orthologues in the tree are indicated (Lp, L. pneumophila; Ab, A. baylyi; Pa, P. aeruginosa; and Xc, X. campestris). The scale bar indicates the average number of substitutions per site. d Top, multisequence alignment of representative FimT orthologues across six orders (indicated by a coloured line as in c) focusing on their C-terminal region (Lc, Legionella cherrii; La, Legionella anisa; Fd, Fluoribacter dumoffii; Vg, Ventosimonas gracilis; Pc, Pseudomonas chloritidismutans; Ml, Marinicella litoralis; He, Halomonas endophytica; Xt, Xylella taiwanensis; Sp, Shewanella polaris; Si, Shewanella indica; Eh, Ectothiorhodospira haloalkaliphile). Residues are coloured according to sequence identity. Bottom, sequence logo generated from the full multisequence alignment of 196 high-confidence FimTs. Source data are provided as a Source Data file.
