Radical SAM enzyme that catalyzes the addition of the adenosyl radical to the double bond of 3-[(1-carboxyvinyl)oxy]benzoate, leading to aminodeoxyfutalosine (AFL), a key intermediate in the formation of menaquinone (MK, vitamin K2) from chorismate. 3-[(1-carboxyvinyl)-oxy]benzoate + H2O + S-adenosyl-L-methionine = 6-amino-6-deoxyfutalosine + H(+) + hydrogencarbonate + L-methionine Binds 1 [4Fe-4S] cluster. The cluster is coordinated with 3 cysteines and an exchangeable S-adenosyl-L-methionine. Quinol/quinone metabolism; menaquinone biosynthesis. Belongs to the radical SAM superfamily. MqnE family.