Fig. 4: Specificity and conservation of MCPDRK.
From: d-amino acids signal a stress-dependent run-away response in Vibrio cholerae
a, Tree of MCPDRK orthologues. The cladogram was constructed on the basis of MCPDRK sequence homology. Orthologues selected for an extended comparison are highlighted in bold. b, Left: selection of MCPDRK orthologue representatives and the conservation of d-Arg binding residues. Only the residues that differ from the reference protein (VC1313, that is, MCPDRK from V. cholerae El Tor strain N16961, boxed) are labelled. Coloured circles indicate the amino acid type (N, asparagine; D, aspartic acid; T, threonine; W, tryptophan; E, glutamic acid; S, serine; A, alanine; G, glycine). Right: genetic context of the chemoreceptor in several species. Both the MCP and the racemase are highlighted. The percentage of total protein identity (%) is shown. c, Chemotactic response of MCPDRK orthologue proteins to d-Arg. The chemotactic response to d-Arg was tested for ΔmcpDKR cells complemented with several orthologue MCPs expressed under the mcpDKR native promoter. ΔbsrV strain was used as background. −, not complemented ΔmcpDRK; VC, V. cholerae; VV, V. vulnificus; VPA, V. parahaemolyticus; VFU, V. furnissii; VA, V. anguillarum; AF, Aliivibrio fischeri; AH, Aeromonas hydrophyla; VO, V. owensii. Black diamonds represent the mean of 4 independent biological replicates. Significant differences (unpaired t-test) are indicated by **P < 0.01.
