PreQ1-III riboswitch
PreQ1-III riboswitches are a class of riboswitches that bind pre-queuosine1 (PreQ1), a precursor to the modified nucleoside queuosine.[1] PreQ1-III riboswitches are the third class of riboswitches to be discovered that sense this ligand, and are structurally distinct from preQ1-I and preQ1-II riboswitches. Most sequenced examples of preQ1-III riboswitches are obtained from uncultivated metagenome samples, but the few examples in cultivated organisms are present in strains that are known to or suspected to be Faecalibacterium prausnitzii, a species of Gram-positive Clostridia. Known examples of preQ1-III riboswitches are found upstream of queT genes, which are expected to encode transporters of a queuosine derivative. The other two known classes of preQ1 riboswitches are also commonly found upstream of queT genes.
The atomic-resolution structure of a preQ1-III riboswitch has been solved by X-ray crystallography.[2]
References
- ^ a b McCown PJ, Liang JJ, Weinberg Z, Breaker RR (2014). "Structural, Functional, and Taxonomic Diversity of Three PreQ1 Riboswitch Classes". Chem Biol. 21 (7): 880–9. doi:10.1016/j.chembiol.2014.05.015. PMID 25036777.
- ^ Liberman JA, Suddala KC, Aytenfisu A, Chan D, Belashov IA, Salim M, Mathews DH, Spitale RC, Walter NG, Wedekind JE. "Structural analysis of a class III preQ1 riboswitch reveals an aptamer distant from a ribosome-binding site regulated by fast dynamics". Proc. Natl. Acad. Sci. USA. doi:10.1073/pnas.1503955112.