Physical Sciences and Mathematics Commons^™

The Mtr4 Ratchet Helix And Arch Domain Both Function To Promote Rna Unwinding, Lacy L. Taylor, Ryan N. Jackson, Megi Rexhepaj, Alejandra Klauer King, Lindsey K. Lott, Ambro Van Hoof, Sean J. Johnson

Chemistry and Biochemistry Faculty Publications

Mtr4 is a conserved Ski2-like RNA helicase and a subunit of the TRAMP complex that activates exosomemiated 3-5 turnover in nuclear RNA surveillance and processing pathways. Prominent features of the Mtr4 structure include a four-domain ring-like helicase core and a large arch domain that spans the core. The ‘ratchet helix’ is positioned to interact with RNA substrates as they move through the helicase. However, the contribution of the ratchet helix in Mtr4 activity is poorly understood. Here we show that strict conservation along the ratchet helix is particularly extensive for Ski2-like RNA helicases compared to related helicases. Mutation of residues …