title: Effects of nucleotides on ATP-dependent protein translocation into Escherichia coli membrane vesicles.
abstract: We have shown previously that Escherichia coli can translocate the same protein either co- or posttranslationally and that ATP hydrolysis is essential for the posttranslational translocation of the precursors of alkaline phosphatase and OmpA protein into inverted E. coli membrane vesicles. ATP-dependent protein translocation has now been further characterized. In the absence of exogenous Mg2+, dATP, formycin A-5'-triphosphate, ATP-alpha-S, and N1-oxide-ATP could replace ATP, but many other nucleotides were not only ineffective but inhibited ATP-dependent translocation. The inhibitors included nonhydrolyzable ATP analogs, ATP-gamma-S, 8-azido-ATP, AMP, ADP, cyclic AMP, PPi, and tripolyphosphate. On the other hand, adenosine, adenosine 5'-tetraphosphate, and N1,N6-etheno-ATP neither supported nor inhibited translocation. Moreover, photoaffinity labeling of azido-adenine nucleotides rendered membranes inactive for subsequent ATP-dependent protein translocation. These results suggest that protein translocation involves at least an ATP-binding site in the membrane and hydrolysis of ATP and that both the adenosine and phosphate moieties of ATP play a role.
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D000469:Alkaline Phosphatase / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D009711:Nucleotides / Q000494:pharmacology*; D011498:Protein Precursors / Q000378:metabolism*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004792:Enzyme Precursors; D009711:Nucleotides; D011498:Protein Precursors; D000255:Adenosine Triphosphate; D000469:Alkaline Phosphatase; D008274:Magnesium