7uo0
E.coli RNaseP Holoenzyme with Mg2+
Structural highlights
FunctionRNPA_ECOLI RNaseP catalyzes the removal of the 5'-leader sequence from pre-tRNA to produce the mature 5'-terminus. It can also cleave other RNA substrates such as 4.5S RNA. The protein component plays an auxiliary but essential role in vivo by binding to the 5'-leader sequence and broadening the substrate specificity of the ribozyme.[HAMAP-Rule:MF_00227][1] Publication Abstract from PubMedBinding of precursor tRNAs (ptRNAs) by bacterial ribonuclease P (RNase P) involves an encounter complex (ES) that isomerizes to a catalytic conformation (ES*). However, the structures of intermediates and the conformational changes that occur during binding are poorly understood. Here, we show that pairing between the 5' leader and 3'RCCA extending the acceptor stem of ptRNA inhibits ES* formation. Cryo-electron microscopy single particle analysis reveals a dynamic enzyme that becomes ordered upon formation of ES* in which extended acceptor stem pairing is unwound. Comparisons of structures with alternative ptRNAs reveals that once unwinding is completed RNase P primarily uses stacking interactions and shape complementarity to accommodate alternative sequences at its cleavage site. Our study reveals active site interactions and conformational changes that drive molecular recognition by RNase P and lays the foundation for understanding how binding interactions are linked to helix unwinding and catalysis. Structural and mechanistic basis for recognition of alternative tRNA precursor substrates by bacterial ribonuclease P.,Zhu J, Huang W, Zhao J, Huynh L, Taylor DJ, Harris ME Nat Commun. 2022 Aug 31;13(1):5120. doi: 10.1038/s41467-022-32843-7. PMID:36045135[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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