Related Experiment Video
Updated: Mar 3, 2026
13:26
Determination of Protein-ligand Interactions Using Differential Scanning Fluorimetry
Published on: September 13, 2014
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Structural, dynamic, and evolutionary determinants of substrate binding in the tetrameric 6-phosphogluconate
Pablo Maturana1, Pablo Villalobos2, Pietro Roversi3
1Laboratorio de Bioquímica y Biología Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Chile; Department of Plant Biology, University of California, Davis, USA.
Archives of Biochemistry and Biophysics
|March 1, 2026
Summary
Tetrameric 6-phosphogluconate dehydrogenases (6PGDHs) use a unique quaternary-tightening mechanism for substrate binding. This involves C-terminal elements that stabilize the catalytic pocket, differing from dimeric 6PGDHs.
Area of Science:
- Biochemistry
- Structural Biology
- Enzymology
Background:
- 6-Phosphogluconate dehydrogenases (6PGDHs) are crucial enzymes in the oxidative pentose phosphate pathway (oxPPP).
- The catalytic mechanisms of short-chain tetrameric 6PGDHs are less understood compared to their dimeric counterparts.
Purpose of the Study:
- To elucidate the structural and mechanistic basis of substrate recognition in tetrameric 6PGDHs.
- To investigate the role of C-terminal elements in the catalytic mechanism of Gluconobacter oxydans 6PGDH (Go6PGDH).
Main Methods:
- X-ray crystallography (2.0 Å resolution) of Go6PGDH complexed with 6-phosphogluconate (6PG).
- Evolutionary, computational (molecular dynamics), and functional (mutagenesis) analyses.
- Thermodynamic measurements of ligand binding.
Main Results:
- The crystal structure reveals tetrameric Go6PGDH does not undergo domain closure upon 6PG binding.
- Conserved C-terminal elements (ionic lock and latch) mediate tetramer compaction and stabilize a closed catalytic pocket.
- His328 is identified as a key residue coupling C-terminal closure to ligand binding, essential for catalysis.
Conclusions:
- Tetrameric 6PGDHs employ a unique substrate-induced quaternary-tightening mechanism.
- C-terminal adaptation regulates substrate binding and catalysis across the 6PGDH enzyme family.
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