Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8103, USA.
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA.
RNA. 2019 Jan;25(1):23-34. doi: 10.1261/rna.067975.118. Epub 2018 Oct 4.
Many bacteria use flavin mononucleotide (FMN) riboswitches to control the expression of genes responsible for the biosynthesis and transport of this enzyme cofactor or its precursor, riboflavin. Rare variants of FMN riboswitches found in strains of and some other bacteria typically control the expression of proteins annotated as transporters, including multidrug efflux pumps. These RNAs no longer recognize FMN, and differ from the original riboswitch consensus sequence at nucleotide positions normally involved in binding of the ribityl and phosphate moieties of the cofactor. Representatives of one of the two variant subtypes were found to bind the FMN precursor riboflavin and the FMN degradation products lumiflavin and lumichrome. Although the biologically relevant ligand sensed by these variant FMN riboswitches remains uncertain, our findings suggest that many strains of might use rare riboswitches to sense flavin degradation products and activate transporters for their detoxification.
许多细菌使用黄素单核苷酸 (FMN) 核糖开关来控制负责合成和运输这种酶辅因子或其前体核黄素的基因的表达。在 和其他一些细菌的菌株中发现的 FMN 核糖开关的罕见变体通常控制被注释为转运蛋白的蛋白质的表达，包括多药外排泵。这些 RNA 不再识别 FMN，并且与原始核糖开关的共识序列在核苷酸位置上不同，这些位置通常涉及辅因子的核醇和磷酸盐部分的结合。发现两种变体亚型的代表之一能够结合 FMN 前体核黄素以及 FMN 降解产物光黄素和光色霉素。尽管这些变体 FMN 核糖开关所感应的生物相关配体尚不确定，但我们的研究结果表明，许多 菌株可能使用罕见的核糖开关来感应黄素降解产物，并激活转运蛋白以进行解毒。
