Characterization of DbpA, an Escherichia coli DEAD box protein with ATP independent RNA unwinding activity.
DbpA is a putative Escherichia coli ATP dependent RNA helicase belonging to the family of DEAD box proteins. It hydrolyzes ATP in the presence of 23S ribosomal RNA and 93 bases in the peptidyl transferase center of 23S rRNA are sufficient to trigger 100% of the ATPase activity of DbpA. In the present study we characterized the ATPase and RNA unwinding activities of DbpA in more detail. We report that-in contrast to eIF-4A, the prototype of the DEAD box protein family-the ATPase and the helicase activities of DbpA are not coupled. Moreover, the RNA unwinding activity of DbpA is not specific for 23S rRNA, since DbpA is also able to unwind 16S rRNA hybrids. Furthermore, we determined that the ATPase activity of DbpA is triggered to a significant extent not only by the 93 bases of the 23S rRNA previously reported but also by other regions of the 23S rRNA molecule. Since all these regions of 23S rRNA are either part of the 'functional core' of the 50S ribosomal subunit or involved in the 50S assembly, DbpA may play an important role in the ribosomal assembly process.
Böddeker
N
N
Max-Planck-Institut für Molekulare Genetik, AG Ribosomen, Ihnestrasse 73, 14195 Berlin, Germany.
Stade
K
K
Franceschi
F
F
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D053487:DEAD-box RNA Helicases; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D020365:RNA Helicases; D012316:RNA Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D012338:RNA, Ribosomal, 23S / Q000378:metabolism; D012341:RNA, Ribosomal, 5S / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D012341:RNA, Ribosomal, 5S; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D000255:Adenosine Triphosphate; D012316:RNA Nucleotidyltransferases; D000251:Adenosine Triphosphatases; C065908:dbpA protein, E coli; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases