Catalyzes the formation of S-adenosylmethionine from methionine and ATP. The reaction comprises two steps that are both catalyzed by the same enzyme: formation of S-adenosylmethionine (AdoMet) and triphosphate, and subsequent hydrolysis of the triphosphate. ATP + H2O + L-methionine = diphosphate + phosphate + S-adenosyl-L-methionine Binds 2 divalent ions per subunit. The metal ions interact primarily with the substrate (By similarity). Can utilize magnesium, manganese or cobalt (in vitro) (By similarity). Binds 1 potassium ion per subunit. The potassium ion interacts primarily with the substrate (By similarity). Amino-acid biosynthesis; S-adenosyl-L-methionine biosynthesis; S-adenosyl-L-methionine from L-methionine: step 1/1. Homotetramer. During compatible and incompatible interactions with Blumeria graminis f. sp. tritici, especially in the infected epidermis. Induced by abiotic stresses such as wounding, cold, drought, and salt. Belongs to the AdoMet synthase family.