Utilization of host‐derived cysteine‐containing peptides overcomes the restricted sulphur metabolism of Campylobacter jejuni

Abstract

SummaryThe non-glycolytic food-borne pathogen Campylobacter jejuni successfully colonizes the intestine of various hosts in spite of its restricted metabolic properties. While several amino acids are known to be used by C. jejuni as energy sources, none of these have been found to be essential for growth. Here we demonstrated through phenotype microarray analysis that cysteine utilization increases the metabolic activity of C. jejuni. Furthermore, cysteine was crucial for its growth as C. jejuni was unable to synthesize it from sulphate or methionine. Our study showed that C. jejuni compensates this limited anabolic capacity by utilizing sulphide, thiosulphate, glutathione and the dipeptides γGlu-Cys, Cys-Gly and Gly-Cys as sulphur sources and cysteine precursors. A panel of C. jejuni mutants in putative peptidases and peptide transporters were generated and tested for their participation in the catabolism of the cysteine-containing peptides, and the predicted transporter protein CJJ81176_0236 was discovered to facilitate the growth with the dipeptide Cys-Gly, Ile-Arg and Ile-Trp. It was named Campylobacter peptide transporter A (CptA) and is the first representative of the oligopeptide transporter OPT family demonstrated to participate in the glutathione-derivative Cys-Gly catabolism in prokaryotes. Our study provides new insights into how hostand microbiota-derived substrates like sulphide, thiosulphate and short peptides are used by C. jejuni to compensate its restricted metabolic capacities.

Defining the metabolic requirements for the growth and colonization capacity of Campylobacter jejuni

“…CjaA (Cj0982c) is an N-glycosylated 30 kDa lipoprotein attached to the inner membrane (Pawelec et al, 1997; Wyszynska et al, 2008) that binds cysteine (Müller et al, 2005). Its direct involvement in the import of cysteine has not been experimentally proven so far, and growth experiments suggested that CjaA might not be solely involved in the uptake of cysteine (Vorwerk et al, 2014). CjaC (Cj0734c) is a N-glycosylated 28 kDa protein with unknown substrate specificity that is anchored in the cytoplasmic membrane of C. jejuni and shows best homologies to various periplasmic binding proteins of ABC-type amino acid transporters (Pawelec et al, 1998; Wyszynska et al, 2007).…”

“…Whereas the importance of amino acid uptake and utilization for the growth of C. jejuni is well documented, only few studies have investigated the de novo biosynthesis of amino acids in this pathogen, like e.g., the involvement of ilvE and cysM in the synthesis of leucine and cysteine, respectively (Ribardo and Hendrixson, 2011; Vorwerk et al, 2014). Other studies have examined the amino acid biosynthesis capability of C. jejuni by heterologous expression of certain genes of arginine (Hani and Chan, 1994; Hani et al, 1999), cysteine (Garvis et al, 1997), leucine (Labigne et al, 1992) and aromatic amino acid (Wösten et al, 1996) biosynthesis pathways in respective auxotrophic Escherichia coli mutants.…”

“…This variability in peptide catabolism might be the consequence of C. jejuni isolates having variable number of peptidases: GGT, the putative S15 family dipeptidyl-peptidase CJJ81176_1680 or the putative subtilisin-like serine peptidases Cj1365 / CJJ81176_1367 and CJJ81176_1371 occur in a subset of C. jejuni strains (Champion et al, 2005; Hofreuter et al, 2006; Hepworth et al, 2007; Gonzalez et al, 2009; Zautner et al, 2011). Only ggt -positive C. jejuni strains can efficiently use the tripeptide glutathione as carbon/energy (Hofreuter et al, 2008) and cysteine source (Vorwerk et al, 2014). A recent study using the BIOLOG phenotype microarray technology suggested that the C. jejuni NCTC 11168 transporter protein Cj0917c, which has homology to the carbon starvation protein A (CstA) of E. coli , is involved in the catabolism of several tri- and dipeptides (Rasmussen et al, 2013).…”

“…Additional experiments are necessary to demonstrate the growth-promoting effect of respective peptides. Moreover, the Campylobacter peptide transporter A (CptA; CJJ81176_0236), a member of the Proton-dependent Oligopeptide Transporter (POT) family, has been described to promote the growth of C. jejuni 81–176 with the dipeptides Cys-Gly, Arg-Trp and Arg-Ile (Vorwerk et al, 2014). …”

Bacterial peptide transporters: Messengers of nutrition to virulence

“…66 Therefore, it is safe to say that peptide transporters in Gram negative pathogens hold importance in pathogenesis.…”