Catalyzes the stereospecific dehydration of (2S,3S)-2-methylcitrate (2-MC) to yield the cis isomer of 2-methyl-aconitate. (2S,3S)-2-methylcitrate = 2-methyl-cis-aconitate + H2O Organic acid metabolism; propanoate degradation. Present with 2730 molecules/cell in log phase SD medium. Belongs to the PrpD family.