title: Division of Labor in an Oligomer of the DEAD-Box RNA Helicase Ded1p.
abstract: Most aspects of RNA metabolism involve DEAD-box RNA helicases, enzymes that bind and remodel RNA and RNA-protein complexes in an ATP-dependent manner. Here we show that the DEAD-box helicase Ded1p oligomerizes in the cell and in vitro, and unwinds RNA as a trimer. Two protomers bind the single-stranded region of RNA substrates and load a third protomer to the duplex, which then separates the strands. ATP utilization differs between the strand-separating protomer and those bound to the single-stranded region. Binding of the eukaryotic initiation factor 4G to Ded1p interferes with oligomerization and thereby modulates unwinding activity and RNA affinity of the helicase. Our data reveal a strict division of labor between the Ded1p protomers in the oligomer. This mode of oligomerization fundamentally differs from other helicases. Oligomerization represents a previously unappreciated level of regulation for DEAD-box helicase activities.
authors.affiliation: Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Putnam
authors.affiliation: Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
authors.forename: Zhaofeng
authors.initials: Z
authors.lastname: Gao
authors.affiliation: Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; College of Veterinary Medicine, Nanjing Agricultural University, Number 1 Weigang, Nanjing 210095, P.R. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.affiliation: Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; BGI Shenzen, Beishan Industrial Zone, Yantian District, Shenzhen 518083, P.R. China.
authors.forename: Huijue
authors.initials: H
authors.lastname: Jia
authors.affiliation: Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; McArdle Laboratory of Cancer Research, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53726, USA.
authors.forename: Quansheng
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Center for RNA Molecular Biology and Department of Biochemistry, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA. Electronic address: exj13@case.edu.
authors.forename: Eckhard
authors.initials: E
authors.lastname: Jankowsky
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D055162:Biocatalysis; D053487:DEAD-box RNA Helicases / Q000737:chemistry* / Q000502:physiology; D006868:Hydrolysis; D011485:Protein Binding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry; D012330:RNA, Double-Stranded / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000502:physiology
chemical_list: D021122:Protein Subunits; D012330:RNA, Double-Stranded; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; C492152:DED1 protein, S cerevisiae; D053487:DEAD-box RNA Helicases