Non-consecutive enzyme interactions within TCA cycle supramolecular assembly regulate carbon-nitrogen metabolism.

Autor: Jasinska, Weronika, Dindo, Mirco, Cordoba, Sandra M. C., Serohijos, Adrian W. R., Laurino, Paola, Brotman, Yariv, Bershtein, Shimon
Předmět:
Zdroj: Nature Communications; 6/20/2024, Vol. 15 Issue 1, p1-15, 15p
Abstrakt: Enzymes of the central metabolism tend to assemble into transient supramolecular complexes. However, the functional significance of the interactions, particularly between enzymes catalyzing non-consecutive reactions, remains unclear. Here, by co-localizing two non-consecutive enzymes of the TCA cycle from Bacillus subtilis, malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICD), in phase separated droplets we show that MDH-ICD interaction leads to enzyme agglomeration with a concomitant enhancement of ICD catalytic rate and an apparent sequestration of its reaction product, 2-oxoglutarate. Theory demonstrates that MDH-mediated clustering of ICD molecules explains the observed phenomena. In vivo analyses reveal that MDH overexpression leads to accumulation of 2-oxoglutarate and reduction of fluxes flowing through both the catabolic and anabolic branches of the carbon-nitrogen intersection occupied by 2-oxoglutarate, resulting in impeded ammonium assimilation and reduced biomass production. Our findings suggest that the MDH-ICD interaction is an important coordinator of carbon-nitrogen metabolism. Enzymes of central metabolism tend to assemble into transient supramolecular complexes. Here, the authors stoichiometrically perturbed the supramolecular complex of TCA cycle enzymes in B. subtilis and propose that MDH-ICD clustering causes 2-oxoglutartae sequestration by reducing its diffusion rate, a mechanism that has evolved to regulate flux through the carbon-nitrogen metabolic branch-point. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index