SAM-I
Global architecture of the metH-F2 S-adenosylmethione binding riboswitch from Thermoanaerobacter tencongensis.
Recognition of adenosyl moiety of SAM by an internal loop within P3.
Recognition of the methionine moiety by elements of P3 and J1/2 (G11).
Recognition of the positively charged sulfonium moiety by two universally conserved base pairs in P1. The sulfur atom is ~4 脜 from two carbonyl groups (U7 and U88) that provide an electrostatic interaction.