Required for the synthesis of N-(3-hydroxyhexanoyl)homoserine lactone (3-hydroxy-C6-HSL) and N-hexanoylhomoserine lactone (C6-HSL). a fatty acyl-[ACP] + S-adenosyl-L-methionine = an N-acyl-L-homoserine lactone + H(+) + holo-[ACP] + S-methyl-5'-thioadenosine Belongs to the LuxM / VanM family.