Expression, Purification And Crystallization Of Mesaconyl-CoA Intramolecular CoA Transferase In 3-Hydroxypropionate Cycle

Jan Zarzycki supplemented the steps of -hydroxypropionate CO2 fixation cycle in Chloroflexus aurantiacus. At the start of the cycle, two acetyl-CoA molecule turns into Malonyl-CoA through carboxylation. Malonyl-CoA transform into 3-hydroxypropionate under the malonyl-CoA reductase catalysis and converted to propionyl-CoA by propionyl-CoA synthase. Till now, one propionyl-CoA molecule goes to cycle one, one goes to cycle two. And in the cycle two, propionyl-CoA is converted to β-methylmalyl-CoA fist, subsequently dehydrated and generate mesaconyl-Cl-CoA. Mesaconyl-C4-CoA hydratase catalyzes the next reaction and compounds (S)-citramalyl-CoA. The latter is cleaved into pyruvate and acetyl-CoA in the end. However, (S)-citramalyl-CoA mesaconyl-Cl-CoA can not be catalyzed by mesaconyl-C4-CoA hydratase. For which, we conclude that there is an intramoleular CoA transferase participating here so that mesaconyl-Cl-CoA can change to mesaconyl-C4-CoA. Here, we purified the mesaconyl-CoA C1-C4 CoA transferase (MCT) and gained protein crystals to proceed crystallization.