Effects of Ions on Ligand Binding to Pyruvate Kinase: Mapping the Binding Site with Infrared Spectroscopy

What is it about?

Phosphenolpyruvate (PEP) binding to pyruvate kinase was studied in the presence of different mono- and divalent ions in the catalytic sites. The ions affected the structural change of the protein upon binding and the structure of bound PEP. In particular, a β-sheet was perturbed differently when Na+ was present, the conformational change was particularly large with Mn2+ due to a more closed conformation of the complex, and the carboxylate group of PEP interacted in a more defined way with the protein when Mn2+ was present than when other divalent ions were present.

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Why is it important?

The work demonstrates the excellent sensitivity and reproducibility of data obtained with a little applied method to initiate protein reactions in infrared spectroscopy. See also our publication on this method: M. Krasteva, S. Kumar, A. Barth (2006), Spectroscopy 20, 89-94, A dialysis accessory for attenuated total reflection infrared spectroscopy.