Involved in the 3-hydroxypropionate cycle used for autotrophic carbon dioxide fixation, and in the glyoxylate assimilation cycle used to regenerate acetyl-CoA and produce pyruvate as universal precursor for biosynthesis. As a part of the 3-hydroxypropionate cycle, it catalyzes the cleavage of (S)-malyl-CoA to yield acetyl-CoA and glyoxylate. As part of the glyoxylate assimilation cycle, it catalyzes the condensation of glyoxylate with propionyl-CoA to yield (2R,3S)-beta-methylmalyl-CoA, and catalyzes the cleavage of (S)-citramalyl-CoA to yield acetyl-CoA and pyruvate. (S)-malyl-CoA = acetyl-CoA + glyoxylate (2R,3S)-beta-methylmalyl-CoA = glyoxylate + propanoyl-CoA (3S)-citramalyl-CoA = acetyl-CoA + pyruvate Divalent cations such as magnesium or manganese. Inhibited by oxalate. Optimum pH is 7.1. Optimum temperature is 70 degrees Celsius. Homohexamer. Dimer of trimers. Belongs to the HpcH/HpaI aldolase family.