8b0i
CryoEM structure of bacterial RapZ.GlmZ complex central to the control of cell envelope biogenesis
Structural highlights
FunctionRAPZ_ECOLI Modulates the synthesis of GlmS, by affecting the processing and stability of the regulatory small RNA GlmZ. When glucosamine-6-phosphate (GlcN6P) concentrations are high in the cell, RapZ binds GlmZ and targets it to cleavage by RNase E. Consequently, GlmZ is inactivated and unable to activate GlmS synthesis. Under low GlcN6P concentrations, RapZ is sequestered and inactivated by an other regulatory small RNA, GlmY, preventing GlmZ degradation and leading to synthesis of GlmS (PubMed:17824929, PubMed:23475961). Displays ATPase and GTPase activities in vitro. Can also hydrolyze pNPP (PubMed:19074378).[1] [2] [3] Publication Abstract from PubMedBiogenesis of the essential precursor of the bacterial cell envelope, glucosamine-6-phosphate (GlcN6P), is controlled by intricate post-transcriptional networks mediated by GlmZ, a small regulatory RNA (sRNA). GlmZ stimulates translation of the mRNA encoding GlcN6P synthtase in Escherichia coli, but when bound by RapZ protein, the sRNA becomes inactivated through cleavage by the endoribonuclease RNase E. Here, we report the cryoEM structure of the RapZ:GlmZ complex, revealing a complementary match of the RapZ tetrameric quaternary structure to structural repeats in the sRNA. The nucleic acid is contacted by RapZ mostly through a highly conserved domain that shares an evolutionary relationship with phosphofructokinase and suggests links between metabolism and riboregulation. We also present the structure of a precleavage intermediate formed between the binary RapZ:GlmZ complex and RNase E that reveals how GlmZ is presented and recognised by the enzyme. The structures provide a framework for understanding how other encounter complexes might guide recognition and action of endoribonucleases on target transcripts, and how structured substrates in polycistronic precursors may be recognised for processing by RNase E. Structure of a bacterial ribonucleoprotein complex central to the control of cell envelope biogenesis.,Islam MS, Hardwick SW, Quell L, Durica-Mitic S, Chirgadze DY, Gorke B, Luisi BF EMBO J. 2023 Jan 16;42(2):e112574. doi: 10.15252/embj.2022112574. Epub 2022 Dec , 12. PMID:36504162[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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