The adenosyl and methionine main-chain moieties of SAM are recognized through hydrogen-bonding into the bulge in P3 and the conserved G in J1/2. The methyl group is recognized indirectly through the charged sulfur, which forms an electrostatic interaction with the negative surface potential created by the tandem AU pairs in the minor groove of P1.
The SAM molecule's adenosyl and methionine main-chain parts are anchored via hydrogen bonds to the bulge in P3 and the conserved G in J1/2. The methyl group is recognized through a secondary interaction involving the positively charged sulfur, which interacts with the negatively charged surface potential generated by the tandem AU pairs in the minor groove of P1.