Projection structure of DtpD (YbgH), a prokaryotic member of the peptide transporter family.
Cellular uptake of di- and tripeptides has been characterized in numerous organisms, and various transporters have been identified. In contrast, structural information on peptide transporters is very sparse. Here, we have cloned, overexpressed, purified, and biochemically characterized DtpD (YbgH) from Escherichia coli, a prokaryotic member of the peptide transporter family. Its homologues in mammals, PEPT1 (SLC15A1) and PEPT2 (SLC15A2), not only transport peptides but also are of relevance for uptake of drugs as they accept a large spectrum of peptidomimetics such as beta-lactam antibiotics, antivirals, peptidase inhibitors, and others as substrates. Uptake experiments indicated that DtpD functions as a canonical peptide transporter and is, therefore, a valid model for structural studies of this family of proteins. Blue native polyacrylamide gel electrophoresis, gel filtration, and transmission electron microscopy of single-DtpD particles suggest that the transporter exists in a monomeric form when solubilized in detergent. Two-dimensional crystallization of DtpD yielded first tubular crystals that allowed the determination of a projection structure at better than 19 A resolution. This structure of DtpD represents the first structural view of a member of the peptide transporter family.
Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, San Diego, La Jolla, CA 92093, USA.
Fabio
F
Casagrande
Daniel
D
Harder
Andreas
A
Schenk
Marcel
M
Meury
Zohre
Z
Ucurum
Andreas
A
Engel
Dietmar
D
Weitz
Hannelore
H
Daniel
Dimitrios
D
Fotiadis
D002850:Chromatography, Gel; D003460:Crystallization; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D017434:Protein Structure, Tertiary
C545656:DtpD protein, E coli; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C043912:peptide permease