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Publication Abstract from PubMed

CshA is a dimeric DEAD-box helicase that cooperates with ribonucleases for mRNA turnover. The molecular mechanism for how a dimeric DEAD-box helicase aids in RNA decay remains unknown. Here, we report the crystal structure and small-angle X-ray scattering solution structure of the CshA from Geobacillus stearothermophilus. In contrast to typical monomeric DEAD-box helicases, CshA is exclusively a dimeric protein with the RecA-like domains of each protomer forming a V-shaped structure. We show that the C-terminal domains protruding outward from the tip of the V-shaped structure is critical for mediating strong RNA binding and is crucial for efficient RNA-dependent ATP hydrolysis. We also show that RNA remains bound with CshA during ATP hydrolysis cycles and thus bulk RNAs could be unwound and degraded in a processive manner through cooperation between exoribonucleases and CshA. A dimeric helicase is hence preserved in RNA-degrading machinery for efficient RNA turnover in prokaryotes and eukaryotes.

Structural Insights into a Unique Dimeric DEAD-Box Helicase CshA that Promotes RNA Decay.,Huen J, Lin CL, Golzarroshan B, Yi WL, Yang WZ, Yuan HS Structure. 2017 Mar 7;25(3):469-481. doi: 10.1016/j.str.2017.01.012. Epub 2017, Feb 23. PMID:28238534^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.