SAM-III aptamer enables detection of enzymatic SAM analogue generation

S-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 in situ. Most SAM analogues were recognized, unless they featured an ortho-substituted benzyl ring, indicating potential regulatory effects via SAM riboswitches.