The DEAD box helicase YxiN maintains a closed conformation during ATP hydrolysis.
DEAD box helicases unwind RNA duplexes at the expense of ATP hydrolysis. Recently, unwinding has been demonstrated in the absence of ATP hydrolysis. Herein, we show that ADP.BeF(x) supports RNA unwinding by YxiN, a DEAD box helicase that specifically recognizes a hairpin in 23S rRNA. ADP.AlF(x) and ADP.MgF(x) do not promote RNA unwinding, but all ATP analogues induce a closed conformation of the helicase core as required for RNA unwinding. Our results show that the interdomain cleft in the helicase core closes upon ATP binding at the beginning of the cycle. Reopening occurs after ATP hydrolysis, most likely coupled to phosphate release.
Aregger
Regula
R
University of Basel, Biozentrum, Biophysical Chemistry, Klingelbergstrasse 70, 4056 Basel, Switzerland.
Klostermeier
Dagmar
D
D000255:Adenosine Triphosphate / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D053487:DEAD-box RNA Helicases / Q000737:chemistry* / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D006868:Hydrolysis; D011487:Protein Conformation
D001426:Bacterial Proteins; D000255:Adenosine Triphosphate; C401542:yxiN protein, Bacillus subtilis; D053487:DEAD-box RNA Helicases