Involved in both the tricarboxylic acid (TCA) and methylcitric acid cycles (PubMed:28956599). Has both 2-methylcitrate synthase and citrate synthase activities. Catalyzes the condensation of propionyl-CoA and oxaloacetate to yield 2-methylcitrate (2-MC) and CoA, and the condensation of acetyl-CoA and oxaloacetate to yield citrate and CoA (PubMed:8759838, PubMed:28956599). Has 2.3-fold higher activity as a 2-methylcitrate synthase (PubMed:28956599). Catalyzes the formation of either (2S,3R)- or (2R,3S)-2-methylcitrate (PubMed:28956599). H2O + oxaloacetate + propanoyl-CoA = 2-methylcitrate + CoA + H(+) acetyl-CoA + H2O + oxaloacetate = citrate + CoA + H(+) Carbohydrate metabolism; tricarboxylic acid cycle; isocitrate from oxaloacetate: step 1/2. Expressed in the mother cell at intermediate stages of sporulation under the control of the sigma-E factor. Subject to catabolite repression. Bifunctionality as a citrate and 2-methylcitrate synthase is likely important in the mother cell's physiological milieu. Belongs to the citrate synthase family.