Direct Evidence for Metabolon Formation and Substrate Channeling in Recombinant TCA Cycle Enzymes

Published on 2017-06-16T22:13:36Z (GMT) by
Supramolecular assembly of enzymes into metabolon structures is thought to enable efficient transport of reactants between active sites <i>via</i> substrate channeling. Recombinant versions of porcine citrate synthase (CS), mitochondrial malate dehydrogenase (mMDH), and aconitase (Aco) were found to adopt a homogeneous native-like metabolon structure <i>in vitro</i>. Site-directed mutagenesis performed on highly conserved arginine residues located in the positively charged channel connecting mMDH and CS active sites led to the identification of CS­(R65A) which retained high catalytic efficiency. Substrate channeling between the CS mutant and mMDH was severely impaired and the overall channeling probability decreased from 0.99 to 0.023. This work provides direct mechanistic evidence for the channeling of reaction intermediates, and disruption of this interaction would have important implications on the control of flux in central carbon metabolism.

Cite this collection

Bulutoglu, Beyza; Garcia, Kristen E.; Wu, Fei; Minteer, Shelley D.; Banta, Scott (2017): Direct Evidence for Metabolon Formation and Substrate

Channeling in Recombinant TCA Cycle Enzymes. ACS Publications.

https://doi.org/10.1021/acschembio.6b00523

Retrieved: 11:05, Aug 22, 2017 (GMT)