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. Catalyzes the transfer of CoA moiety from succinyl-CoA to D-citramalate to yield citramalyl-CoA (By similarity). (3R)-citramalate + succinyl-CoA = (3R)-citramalyl-CoA + succinate (R)-malate + succinyl-CoA = (R)-malyl-CoA + succinate Homodimer. Under autotrophic growth conditions. Belongs to the CoA-transferase III family.