Roles of individual domains in the function of DHX29, an essential factor required for translation of structured mammalian mRNAs

• DOI: 10.1073/pnas.1208014109
• Publication Date: 2012-10-10T04:46:11Z
• Authors: Vidya Dhote; Trevor R. Sweeney; Natalia Kim; Christopher U. T....; Tatyana V. Pestova
• Keywords: RNA Helicase A; Nucleoside triphosphate; Eukaryotic initiation factor

On most eukaryotic mRNAs, initiation codon selection involves base-by-base inspection of 5' UTRs by scanning ribosomal complexes. Although the factors 4A/4B/4G can mediate through medium-stability hairpins, more stable structures additionally requires DHX29, a member superfamily 2 DEAH/RNA helicase A (RHA) family that binds to 40S subunits and possesses 40S-stimulated nucleoside triphosphatase (NTPase) activity. Here, sequence alignment structural modeling indicated DHX29 comprises unique 534-aa-long N-terminal region (NTR), central catalytic RecA1/RecA2 domains containing large insert in RecA2 domain, C-terminal part, which includes winged-helix, ratchet, oligonucleotide/oligosaccharide-binding (OB) are characteristic DEAH/RHA helicases. Functional characterization revealed specific targeting is required for DHX29's activity determined elements map NTR half winged-helix domain. The ribosome-binding determinant located was identified as putative double-stranded RNA-binding Mutational analyses confirmed essential role NTP hydrolysis function validated significance β-hairpin protruding from RecA2. played an autoinhibitory suppressing intrinsic NTPase but not its initiation. Deletion OB domain also increased basal activity, importantly, abrogated responsiveness stimulation, abolished This finding suggests helicases, plays important their cycle.