8GK8 image
Entry Detail
PDB ID:
8GK8
Keywords:
Title:
R21A Staphylococcus aureus pyruvate carboxylase
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2023-03-17
Release Date:
2023-08-30
Method Details:
Experimental Method:
Resolution:
2.68 Å
R-Value Free:
0.30
R-Value Work:
0.24
R-Value Observed:
0.25
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Pyruvate carboxylase
Mutations:R21A
Chain IDs:A (auth: C), B, C (auth: D), D (auth: A)
Chain Length:1151
Number of Molecules:4
Biological Source:Staphylococcus aureus
Primary Citation
Allosteric Site at the Biotin Carboxylase Dimer Interface Mediates Activation and Inhibition in Staphylococcus aureus Pyruvate Carboxylase.
Biochemistry 62 2632 2644 (2023)
PMID: 37603581 DOI: 10.1021/acs.biochem.3c00280

Abstact

Allosteric regulation of the essential anaplerotic enzyme, pyruvate carboxylase (PC), is vital for metabolic homeostasis. PC catalyzes the bicarbonate- and ATP-dependent carboxylation of pyruvate to form oxaloacetate. Dysregulation of PC activity can impact glucose and redox metabolism, which contributes to the pathogenicity of many diseases. To maintain homeostasis, PC is allosterically activated by acetyl-CoA and allosterically inhibited by l-aspartate. In this study, we further characterize the molecular basis of allosteric regulation in Staphylococcus aureus PC (SaPC) using slowly/nonhydrolyzable dethia analogues of acetyl-CoA and site-directed mutagenesis of residues at the biotin carboxylase homodimer interface. The dethia analogues fully activate SaPC but demonstrate significantly reduced binding affinities relative to acetyl-CoA. Residues Arg21, Lys46, and Glu418 of SaPC are located at the biotin carboxylase dimer interface and play a critical role in both allosteric activation and inhibition. A structure of R21A SaPC in complex with acetyl-CoA reveals an intact molecule of acetyl-CoA bound at the allosteric site, offering new molecular insights into the acetyl-CoA binding site. This study demonstrates that the biotin carboxylase domain dimer interface is a critical allosteric site in PC, serving as a convergence point for allosteric activation by acetyl-CoA and inhibition by l-aspartate.

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