Division of Labor in an Oligomer of the DEAD-Box RNA Helicase Ded1p.

Andrea A Putnam, Zhaofeng Gao, Fei Liu, Huijue Jia, Quansheng Yang, Eckhard Jankowsky

Molecular cell 2015 Aug 20

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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. Copyright © 2015 Elsevier Inc. All rights reserved.

Citation

Andrea A Putnam, Zhaofeng Gao, Fei Liu, Huijue Jia, Quansheng Yang, Eckhard Jankowsky. Division of Labor in an Oligomer of the DEAD-Box RNA Helicase Ded1p. Molecular cell. 2015 Aug 20;59(4):541-52