title: RNA Remodeling Activity of DEAD Box Proteins Tuned by Protein Concentration, RNA Length, and ATP.
abstract: DEAD box RNA helicases play central roles in RNP biogenesis. We reported earlier that LAF-1, a DEAD box RNA helicase in C. elegans, dynamically interacts with RNA and that the interaction likely contributes to the fluidity of RNP droplets. Here we investigate the molecular basis of the interaction of RNA with LAF-1 and its human homolog, DDX3X. We show that both LAF-1 and DDX3X, at low concentrations, are monomers that induce tight compaction of single-stranded RNA. At high concentrations, the proteins are multimeric and dynamically interact with RNA in an RNA length-dependent manner. The dynamic LAF-1-RNA interaction stimulates RNA annealing activity. ATP adversely affects the RNA remodeling ability of LAF-1 by suppressing the affinity, dynamics, and annealing activity of LAF-1, suggesting that ATP may promote disassembly of the RNP complex. Based on our results, we postulate a plausible molecular mechanism underlying the dynamic equilibrium of the LAF-1 RNP complex.
authors.affiliation: Bioengineering Department, University of Illinois, 1304 West Springfield Avenue, Urbana, IL 61801, USA.
authors.forename: Younghoon
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Biophysics Department, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA; Physics Frontier Center (Center for Physics of Living Cells), University of Illinois, 1110 West Green Street, Urbana, IL 61801, USA. Electronic address: smyong@jhu.edu.
authors.forename: Sua
authors.initials: S
authors.lastname: Myong
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D053487:DEAD-box RNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D029742:Caenorhabditis elegans Proteins; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D012313:RNA; D000255:Adenosine Triphosphate; C119332:DDX3X protein, human; D053487:DEAD-box RNA Helicases