4peg
Dbr1 in complex with guanosine-5'-monophosphate
Structural highlights
FunctionDBR1_ENTH1 Cleaves the 2'-5' phosphodiester linkage at the branch point of excised lariat intron RNA and converts them into linear molecules that can be subsequently degraded, thereby facilitating ribonucleotide turnover.[1] [2] [3] Publication Abstract from PubMedThe enzymatic processing of cellular RNA molecules requires selective recognition of unique chemical and topological features. The unusual 2',5'-phosphodiester linkages in RNA lariats produced by the spliceosome must be hydrolyzed by the intron debranching enzyme (Dbr1) before they can be metabolized or processed into essential cellular factors, such as snoRNA and miRNA. Dbr1 is also involved in the propagation of retrotransposons and retroviruses, although the precise role played by the enzyme in these processes is poorly understood. Here, we report the first structures of Dbr1 alone and in complex with several synthetic RNA compounds that mimic the branchpoint in lariat RNA. The structures, together with functional data on Dbr1 variants, reveal the molecular basis for 2',5'-phosphodiester recognition and explain why the enzyme lacks activity toward 3',5'-phosphodiester linkages. The findings illuminate structure/function relationships in a unique enzyme that is central to eukaryotic RNA metabolism and set the stage for the rational design of inhibitors that may represent novel therapeutic agents to treat retroviral infections and neurodegenerative disease. Structural basis of lariat RNA recognition by the intron debranching enzyme Dbr1.,Montemayor EJ, Katolik A, Clark NE, Taylor AB, Schuermann JP, Combs DJ, Johnsson R, Holloway SP, Stevens SW, Damha MJ, Hart PJ Nucleic Acids Res. 2014 Aug 14. pii: gku725. PMID:25123664[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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