A binding-lipoprotein-dependent oligopeptide transport system in Streptococcus gordonii essential for uptake of hexa- and heptapeptides

Streptococcus (S) gordonii has a hexa-heptapeptide permease uptake system with a high degree of genetic similarity to that found in S. pneumoniae. The S. gordonii system differs only in its binding-protein requirements. Specifically, the cytoplasmic-membrane bound lipoproteins HppA, HppG and HppH were found to be necessary for peptide utilization in the bacterium, whenever the peptides to be processed had five to seven amino acid residues. HppA and HppH, in particular, were crucial to oligopeptide uptake.