The SSU Processome Component Utp25p is a Pseudohelicase

Abstract

RNA helicases are involved in nearly all aspects of RNA metabolism and factor prominently in ribosome assembly. The SSU processome includes 10 helicases and many helicase-cofactors. Together, they mediate the structural rearrangements that occur during ribosomal SSU assembly. During the identification of the SSU processome component Utp25, it was noticed that the protein displays some sequence similarity to DEAD-box RNA helicases and is essential for growth. Interestingly, mutational ablation showed that Utp25s DEAD-box motifs are dispensable. Here, we use AlphaFold to show that Utp25 retains considerable structural similarity to DEAD-box helicases and is the first fully validated pseudohelicase.