The PTR family: a new group of peptide transporters |
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Authors: | Henry-York Steiner Fred Naider Jeffrey M Becker |
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Institution: | Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996-0645, USA.;Department of Chemistry, College of Staten Island, City University at New York, Staten Island, New York 10301, USA. |
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Abstract: | 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. |
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