Evaluating inositol phospholipid interactions with inward rectifier potassium channels and characterising their role in disease

Membrane proteins are frequently modulated by specific protein-lipid interactions. The activation of human inward rectifying potassium (hKir) channels by phosphoinositides (PI) has been well characterised. Here, we apply a coarse-grained molecular dynamics free-energy perturbation (CG-FEP) protocol...

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Bibliographic Details
Published in:Communications chemistry 2020-10, Vol.3 (1), p.147, Article 147
Main Authors: Pipatpolkai, Tanadet, Corey, Robin A, Proks, Peter, Ashcroft, Frances M, Stansfeld, Phillip J
Format: Article
Language:English
Subjects:
Affinity
Binding
Channels
Free energy
Lipids
Membranes
Molecular dynamics
Mutation
Perturbation
Phosphatidylcholine
Phospholipids
Potassium
Proteins
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Summary:Membrane proteins are frequently modulated by specific protein-lipid interactions. The activation of human inward rectifying potassium (hKir) channels by phosphoinositides (PI) has been well characterised. Here, we apply a coarse-grained molecular dynamics free-energy perturbation (CG-FEP) protocol to capture the energetics of binding of PI lipids to hKir channels. By using either a single- or multi-step approach, we establish a consistent value for the binding of PIP to hKir channels, relative to the binding of the bulk phosphatidylcholine phospholipid. Furthermore, by perturbing amino acid side chains on hKir6.2, we show that the neonatal diabetes mutation E179K increases PIP affinity, while the congenital hyperinsulinism mutation K67N results in a reduced affinity. We show good agreement with electrophysiological data where E179K exhibits a reduction in neomycin sensitivity, implying that PIP binds more tightly E179K channels. This illustrates the application of CG-FEP to compare affinities between lipid species, and for annotating amino acid residues.
ISSN:2399-3669
2399-3669
DOI:10.1038/s42004-020-00391-0