SAH riboswitch

[1] When the coenzyme S-adenosylmethionine (SAM) is used in a methylation reaction, SAH is produced.

SAH riboswitches typically up-regulate genes involved in recycling SAH to create more SAM (or the metabolically related methionine).

This is particularly relevant to cells, because high levels of SAH can be toxic.

[2] Originally identified by bioinformatics,[3] SAH riboswitches are apparent in many species of bacteria, predominantly certain Pseudomonadota and Actinomycetota.

The atomic-resolution 3-dimensional structure of an SAH riboswitch has been solved using X-ray crystallography.

Consensus secondary structure of SAH riboswitches. Layout is similar to that used in a published depiction. [ 1 ] Three base pairs in this secondary structure were incorrectly predicted, while an additional base pair is missing, as revealed by an atomic-resolution tertiary structure. [ 4 ]