NAD+ binding to the Escherichia coli K(+)-uptake protein TrkA and sequence similarity between TrkA and domains of a family of dehydrogenases suggest a role for NAD+ in bacterial transport.
The nucleotide sequence of trkA, a gene encoding a surface component of the constitutive K(+)-uptake systems TrkG and TrkH from Escherichia coli, was determined. The structure of the TrkA protein deduced from the nucleotide sequence accords with the view that TrkA is peripherally bound to the inner side of the cytoplasmic membrane. Analysis by a dot matrix revealed that TrkA is composed of similar halves. The N-terminal part of each TrkA half (residues 1-130 and 234-355, respectively) is similar to the complete NAD(+)-binding domain of NAD(+)-dependent dehydrogenases. The C-terminal part of each TrkA half (residues 131-233 and 357-458, respectively) aligns with the first 100 residues of the catalytic domain of glyceraldehyde-3-phosphate dehydrogenase. Strong u.v. illumination at 252 nm led to cross-linking of NAD+ or NADH, but not of ATP to the isolated TrkA protein.
Schlösser
A
A
Abteilung Mikrobiologie, Universität Osnabrück, Germany.
Hamann
A
A
Bossemeyer
D
D
Schneider
E
E
Bakker
E P
EP
D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism; D016366:Open Reading Frames / Q000235:genetics; D010088:Oxidoreductases / Q000145:classification / Q000235:genetics; D011188:Potassium / Q000378:metabolism*; D011489:Protein Denaturation; D020917:Receptor, trkA; D016415:Sequence Alignment; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014466:Ultraviolet Rays
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C068021:MalK protein, Bacteria; C489398:MalK protein, E coli; D008565:Membrane Proteins; D009711:Nucleotides; D009243:NAD; D010088:Oxidoreductases; D020917:Receptor, trkA; D011188:Potassium