The PTR family: a new group of peptide transporters

• Published in: Molecular microbiology Vol. 16; no. 5; p. 825
• Main Authors: Steiner, H Y, Naider, F, Becker, J M
• Format: Journal Article
• Language: English
• Published: England 01-06-1995
• Subjects: Amino Acid Sequence; Bacteria - metabolism; Carrier Proteins - chemistry; Carrier Proteins - metabolism; Cell Membrane - metabolism; Consensus Sequence; Conserved Sequence; Glycosylation; Humans; Molecular Sequence Data; Peptides - metabolism; Phosphorylation; Phylogeny; Protein Processing, Post-Translational; Sequence Homology, Amino Acid
• ISSN: 0950-382X
• DOI: 10.1111/j.1365-2958.1995.tb02310.x

The transport of peptides into cells is a well-documented biological phenomenon which is accomplished by specific, energy-dependent transporters found in a number of organisms as diverse as bacteria and humans. Until recently, the majority of peptide transporters cloned and characterized were found to be proteins of the ATP-binding cassette (ABC) family. We report the identification of a new family of peptide transporters, which we call the PTR family. This group of proteins, distinct from the ABC-type peptide transporters, was uncovered by sequence analyses of a number of recently discovered peptide transport proteins. Alignment of these proteins demonstrated a high number of identical and similar residues and identified conserved glycosylation and phosphorylation sites, as well as a structural motif unique to this group of proteins. Cluster analysis among the proteins indicated these sequences were indeed related and could be further divided into two subfamilies. A phylogenetic analysis of these new peptide transport sequences, compared to over 50 other peptide and membrane-bound transporters, showed that these proteins comprise a distinct, separate group of proteins.