title: Mutation of the arginine finger in the active site of Escherichia coli DbpA abolishes ATPase and helicase activity and confers a dominant slow growth phenotype.
abstract: Escherichia coli DEAD-box protein A (DbpA) is an ATP-dependent RNA helicase with specificity for 23S ribosomal RNA. Although DbpA has been extensively characterized biochemically, its biological function remains unknown. Previous work has shown that a DbpA deletion strain is viable with little or no effect on growth rate. In attempt to elucidate a phenotype for DbpA, point mutations were made at eleven conserved residues in the ATPase active site, which have exhibited dominant-negative phenotypes in other DExD/H proteins. Biochemical analysis of these DbpA mutants shows the expected decrease in RNA-dependent ATPase activity and helix unwinding activity. Only the least biochemically active mutation, R331A, produces small colony phenotype and a reduced growth rate. This dominant slow growth mutant will be valuable to determine the cellular function of DbpA.
authors.affiliation: Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208, USA.
authors.forename: Lisa M Sharpe
authors.initials: LM
authors.lastname: Elles
authors.forename: Olke C
authors.initials: OC
authors.lastname: Uhlenbeck
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020816:Amino Acid Motifs; D001120:Arginine / Q000737:chemistry; D001665:Binding Sites; D053487:DEAD-box RNA Helicases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D017354:Point Mutation; D012313:RNA / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D012313:RNA; D001120:Arginine; D000251:Adenosine Triphosphatases; C065908:dbpA protein, E coli; D053487:DEAD-box RNA Helicases