PDBsum entry 5ivl

Hydrolase

PDB id: 5ivl

Contents

Protein chains

413 a.a.

Ligands

SO4 ×4

Waters ×209

References listed in PDB file

Key reference

• Title: Structural insights into a unique dimeric dead-Box helicase csha that promotes RNA decay.
• Authors: J.Huen, C.L.Lin, B.Golzarroshan, W.L.Yi, W.Z.Yang, H.S.Yuan.
• Ref.: Structure, 2017, 25, 469-481. [DOI no: 10.1016/j.str.2017.01.012]
• PubMed id: 28238534

Abstract

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.