Comparison of the localization and post-translational modification of Campylobacter coli CjaC and its homolog from Campylobacter jejuni, Cj0734c/HisJ.

Abstract

Campylobacter is an asaccharolytic microorganism which uses amino acids as a source of carbon and energy. CjaC/HisJ is a ligand-binding protein, a component of the ABC transport system. Campylobacter CjaC/HisJ is post-translationally modified by glycosylation. The number of glycosylation motifs present in the CjaC protein is species-specific. C. coli CjaC has two and C. jejuni one motif (E/DXNYS/T) which serves as a glycan acceptor. Although the two C. coli CjaC motifs have identical amino-acid sequences they are not glycosylated with the same efficiency. The efficacy of CjaC glycosylation in Escherichia coli containing the Campylobacter pgl locus is also rather low compared to that observed in the native host. The CjaC localization is host-dependent. Despite being a lipoprotein, CjaC is recovered in E. coli from the periplasmic space whereas in Campylobacter it is anchored to the inner membrane.