Riboswitches are highly conserved RNA elements that located in the 5'-UTR of mRNAs, which undergo real-time structure conformational change to achieve the regulation of downstream gene expression by sensing their cognate ligands. S-adenosylmethionine (SAM) is a ubiquitous methyl donor for transmethylation reactions in all living organisms. SAM riboswitch is one of the most abundant riboswitches that bind to SAM with high affinity and selectivity, serving as regulatory modules in multiple metabolic pathways. To date, seven SAM-specific riboswitch classes that belong to four families, one SAM/SAH riboswitch and one SAH riboswitch have been identified. Each SAM riboswitch family has a well-organized tertiary core scaffold to support their unique ligand-specific binding pocket. In this review, we summarize the current research progress on the distribution, structure, ligand recognition and gene regulation mechanism of these SAM-related riboswitch families, and further discuss their evolutionary prospects and potential applications.
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http://dx.doi.org/10.1007/s11427-022-2188-7 | DOI Listing |
Nat Chem Biol
January 2025
Institute of Organic Chemistry, Julius-Maximilians-Universität Würzburg, Würzburg, Germany.
Ribozymes that catalyze site-specific RNA modification have recently gained increasing interest for their ability to mimic methyltransferase enzymes and for their application to install molecular tags. Recently, we reported SAMURI as a site-specific alkyltransferase ribozyme using S-adenosylmethionine (SAM) or a stabilized analog to transfer a methyl or propargyl group to N of an adenosine. Here, we report the crystal structures of SAMURI in the postcatalytic state.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstr. 5-13, Haus F, D-81377 Munich, Germany.
-Adenosyl-L-methionine (SAM) is crucial for methylation and tightly controlled in cells. We examined SAM-III riboswitch response to 17 SAM analogues and used a Spinach/SAM aptasensor to monitor their enzymatic formation . Most SAM analogues were recognized, unless they featured an -substituted benzyl ring, indicating potential regulatory effects SAM riboswitches.
View Article and Find Full Text PDFInt J Mol Sci
October 2024
College of Biological Science and Medical Engineering, Donghua University, Shanghai 201620, China.
Tandem SAM-II/SAM-V riboswitch belongs to a class of riboswitches found in the marine bacterium ' Pelagibacter ubique'. Previous studies have demonstrated that these riboswitches have the potential for digital modulation of gene expression at both the transcriptional and translational levels. In this study, we investigate the conformational changes in the tandem SAM-II/SAM-V riboswitch binding to S-adenosylmethionine (SAM) using selective 2'-hydroxyl acylation analyzed by the primer extension (SHAPE) assay, small-angle X-ray scattering (SAXS), and oligos depressing probing.
View Article and Find Full Text PDFRNA
December 2024
Department of Biological Chemistry, Center for RNA Biomedicine, Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
RNAs are often studied in nonnative sequence contexts to facilitate structural studies. However, seemingly innocuous changes to an RNA sequence may perturb the native structure and generate inaccurate or ambiguous structural models. To facilitate the investigation of native RNA secondary structure by selective 2' hydroxyl acylation analyzed by primer extension (SHAPE), we engineered an approach that couples minimal enzymatic steps to RNA chemical probing and mutational profiling (MaP) reverse transcription (RT) methods-a process we call template switching and mutational profiling (Switch-MaP).
View Article and Find Full Text PDFBiochemistry
October 2024
Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 28599-3290, United States.
Single-molecule correlated chemical probing (smCCP) is an experimentally concise strategy for characterizing higher-order structural interactions in RNA. smCCP data yield rich, but complex, information about base pairing, conformational ensembles, and tertiary interactions. To date, through-space communication specifically measuring RNA tertiary structure has been difficult to isolate from structural communication reflective of other interactions.
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