New insights into the substrate specificities of proton-coupled oligopeptide transporters from E. coli by a pH sensitive assay.
Proton-coupled oligopeptide transporters (POTs) are secondary active transporters that facilitate di- and tripeptide uptake by coupling it to an inward directed proton electrochemical gradient. Here the substrate specificities of Escherichia coli POTs YdgR, YhiP and YjdL were investigated by means of a label free transport assay using the hydrophilic pH sensitive dye pyranine and POT overexpressing E. coli cells. The results confirm and extend the functional knowledge on E. coli POTs. In contrast to previous assumptions, alanine and trialanine appears to be substrates of YjdL, albeit poor compared to dipeptides. Similarly tetraalanine apparently is a substrate of both YdgR and YhiP.
Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Bala K
BK
Prabhala
Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Nanda G
NG
Aduri
Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Johanne M
JM
Jensen
Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Heidi A
HA
Ernst
Health Biotechnology Divisions, National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.
Nida
N
Iram
Health Biotechnology Divisions, National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan.
Moazur
M
Rahman
Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. Electronic address: om@sund.ku.dk.
Osman
O
Mirza
D019943:Amino Acid Substitution; D004151:Dipeptides / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D013379:Substrate Specificity
D004151:Dipeptides; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins
Bioassay; POTs; Peptides; Proton; Pyranine