Alternate routes to mnm 5 s 2 U synthesis in Gram-positive bacteria.
| Autor: | Jaroch M; Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA., Sun G; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.; Singapore-MIT Alliance for Research and Technology, CREATE Tower, Singapore., Tsui H-CT; Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA., Reed C; Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA., Sun J; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.; Singapore-MIT Alliance for Research and Technology, CREATE Tower, Singapore., Jörg M; Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA., Winkler ME; Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA., Rice KC; Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA., Dziergowska A; Institute of Organic Chemistry, Lodz University of Technology, Łódź, Poland., Stich TA; Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, USA., Dedon PC; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.; Singapore-MIT Alliance for Research and Technology, CREATE Tower, Singapore., Dos Santos PC; Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, USA., de Crécy-Lagard V; Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA.; University of Florida Genetics Institute, Gainesville, Florida, USA. |
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| Jazyk: | angličtina |
| Zdroj: | Journal of bacteriology [J Bacteriol] 2024 Apr 18; Vol. 206 (4), pp. e0045223. Date of Electronic Publication: 2024 Mar 29. |
| DOI: | 10.1128/jb.00452-23 |
| Abstrakt: | The wobble bases of tRNAs that decode split codons are often heavily modified. In bacteria, tRNA Glu, Gln, Asp contains a variety of xnm 5 s 2 U derivatives. The synthesis pathway for these modifications is complex and fully elucidated only in a handful of organisms, including the Gram-negative Escherichia coli K12 model. Despite the ubiquitous presence of mnm 5 s 2 U modification, genomic analysis shows the absence of mnmC orthologous genes, suggesting the occurrence of alternate biosynthetic schemes for the conversion of cmnm 5 s 2 U to mnm 5 s 2 U. Using a combination of comparative genomics and genetic studies, a member of the YtqA subgroup of the radical Sam superfamily was found to be involved in the synthesis of mnm 5 s 2 U in both Bacillus subtilis and Streptococcus mutans . This protein, renamed MnmL, is encoded in an operon with the recently discovered MnmM methylase involved in the methylation of the pathway intermediate nm 5 s 2 U into mnm 5 s 2 U in B. subtilis . Analysis of tRNA modifications of both S. mutans and Streptococcus pneumoniae shows that growth conditions and genetic backgrounds influence the ratios of pathway intermediates owing to regulatory loops that are not yet understood. The MnmLM pathway is widespread along the bacterial tree, with some phyla, such as Bacilli, relying exclusively on these two enzymes. Although mechanistic details of these newly discovered components are not fully resolved, the occurrence of fusion proteins, alternate arrangements of biosynthetic components, and loss of biosynthetic branches provide examples of biosynthetic diversity to retain a conserved tRNA modification in Nature.IMPORTANCEThe xnm 5 s 2 U modifications found in several tRNAs at the wobble base position are widespread in bacteria where they have an important role in decoding efficiency and accuracy. This work identifies a novel enzyme (MnmL) that is a member of a subgroup of the very versatile radical SAM superfamily and is involved in the synthesis of mnm 5 s 2 U in several Gram-positive bacteria, including human pathogens. This is another novel example of a non-orthologous displacement in the field of tRNA modification synthesis, showing how different solutions evolve to retain U34 tRNA modifications. Competing Interests: The authors declare no conflict of interest. |
| Databáze: | MEDLINE |
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