8-azidoadenosine-5--triphosphate and Chromosome-Deletion

The nucleotide-binding component of the high-affinity ribose transport system of Escherichia coli, RbsA, was overproduced from a T7-7 expression vector, and the protein was purified. Biochemical analyses of the purified protein indicated that the ATP analogues, 5'-FSBA and 8-azido ATP, covalently labeled the protein, a reaction that was inhibited by ATP, but not by GTP or CTP. The pure protein exhibited low-level ATPase activity with a K(m) of about 140 microM. Analyses of bacterial strains carrying chromosomal deletions of rbsA and other rbs genes suggested that RbsA is important for the chemotaxis function, a surprising result that was not anticipated from previous studies. However, an inconsistency between the several results from deletion strains raises questions regarding the interpretations of the in vivo data.

Topics: Adenosine; Adenosine Triphosphatases; Adenosine Triphosphate; Affinity Labels; Animals; ATP-Binding Cassette Transporters; Autoradiography; Azides; Blotting, Western; Carrier Proteins; Chemotaxis; Chromosome Deletion; DNA, Bacterial; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Escherichia coli Proteins; Gene Deletion; Gene Expression; Genetic Vectors; Membrane Transport Proteins; Operon; Photolysis; Plasmids; Rabbits; Recombinant Proteins