Abstract
A rare chemotaxis receptor, Tlp11, has been previously identified in invasive strains of
Campylobacter jejuni, the most prevalent cause of bacterial gastroenteritis worldwide. Here we
use glycan and small-molecule arrays, as well as surface plasmon resonance, to show that
Tlp11 specifically interacts with galactose. Tlp11 is required for the chemotactic response of
C. jejuni to galactose, as shown using wild type, allelic inactivation and addition mutants. The
inactivated mutant displays reduced virulence in vivo, in a model of chicken colonization. The
Tlp11 sensory domain represents the first known sugar-binding dCache_1 domain, which is the
most abundant family of extracellular sensors in bacteria. The Tlp11 signalling domain
interacts with the chemotaxis scaffolding proteins CheV and CheW, and comparative
genomic analysis indicates a likely recent evolutionary origin for Tlp11.We propose to rename
Tlp11 as CcrG, Campylobacter ChemoReceptor for Galactose.