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Cryo-EM structure of MLE in complex with UUC RNA and ADP
Structural highlights
FunctionMLE_DROME Required in males for dosage compensation of X chromosome linked genes. Mle, msl-1 and msl-3 are colocalized on X chromosome. Each of the msl proteins requires all the other msls for wild-type X-chromosome binding. Probably unwinds double-stranded DNA and RNA in a 3' to 5' direction.[1] Publication Abstract from PubMedRNA unwinding by DExH-type helicases underlies most RNA metabolism and function. It remains unresolved if and how the basic unwinding reaction of helicases is regulated by auxiliary domains. We explored the interplay between the RecA and auxiliary domains of the RNA helicase maleless (MLE) from Drosophila using structural and functional studies. We discovered that MLE exists in a dsRNA-bound open conformation and that the auxiliary dsRBD2 domain aligns the substrate RNA with the accessible helicase tunnel. In an ATP-dependent manner, dsRBD2 associates with the helicase module, leading to tunnel closure around ssRNA. Furthermore, our structures provide a rationale for blunt-ended dsRNA unwinding and 3'-5' translocation by MLE. Structure-based MLE mutations confirm the functional relevance of our model for RNA unwinding. Our findings contribute to our understanding of the fundamental mechanics of auxiliary domains in DExH helicase MLE, which serves as a model for its human ortholog and potential therapeutic target, DHX9/RHA. Structural basis of RNA-induced autoregulation of the DExH-type RNA helicase maleless.,Jagtap PKA, Muller M, Kiss AE, Thomae AW, Lapouge K, Beck M, Becker PB, Hennig J Mol Cell. 2023 Dec 7;83(23):4318-4333.e10. doi: 10.1016/j.molcel.2023.10.026. , Epub 2023 Nov 20. PMID:37989319[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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