6ZNG

A rotary mechanism for allostery in bacterial hybrid malic enzymes.

(2021) Nat Commun 12: 1228-1228

• PubMed: 33623032 Search on PubMedSearch on PubMed Central
• DOI: https://doi.org/10.1038/s41467-021-21528-2
• Primary Citation of Related Structures:  
  6ZN4, 6ZN7, 6ZN9, 6ZNE, 6ZNG, 6ZNJ, 6ZNK, 6ZNR, 6ZNT, 6ZNU


• PubMed Abstract: 
  

  Bacterial hybrid malic enzymes (MaeB grouping, multidomain) catalyse the transformation of malate to pyruvate, and are a major contributor to cellular reducing power and carbon flux. Distinct from other malic enzyme subtypes, the hybrid enzymes are regulated by acetyl-CoA, a molecular indicator of the metabolic state of the cell. Here we solve the structure of a MaeB protein, which reveals hybrid enzymes use the appended phosphotransacetylase (PTA) domain to form a hexameric sensor that communicates acetyl-CoA occupancy to the malic enzyme active site, 60 Å away. We demonstrate that allostery is governed by a large-scale rearrangement that rotates the catalytic subunits 70° between the two states, identifying MaeB as a new model enzyme for the study of ligand-induced conformational change. Our work provides the mechanistic basis for metabolic control of hybrid malic enzymes, and identifies inhibition-insensitive variants that may find utility in synthetic biology.

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Organizational Affiliation: 

Department of Biosciences, University of Birmingham, Birmingham, UK. [email protected].