S-adenosylmethionine (SMA) is a riboswitch, which are structured noncoding RNA domains that selectively bind metabolites and control gene expression. Nearly all examples of the known riboswitches reside in noncoding regions of messenger RNAs where they control transcription or translation.
Function
Stable binding of SAM when adequate amounts are present results in it acting as a transcriptional terminator which turns off gene expression. To understand the function and specificity of SAM as a riboregulator it is important to first understand the key structures of SAM. The key architecture of SAM is composed of ligand-induced interactions between one helix and the 3' side of another helix surrounding the SAM ligand as well as hydrogen bonding interactions between the adenosine base of SAM and interactions between the main chain atoms of methionine with nucleotide interactions.
The adenine base of SAM, A45 and U57, creates a hydrogen bonding interaction to
Relevance
Structural highlights
