Modulation of the potassium channel KcsA by anionic phospholipids: Role of arginines at the non-annular lipid binding sites
| Autor: | José A. Poveda, Andrés Morales, Carmen Domene, Victoria Oakes, Oscar Millet, Simone Furini, A. Marcela Giudici, M. Lourdes Renart, José M. González-Ros |
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| Přispěvatelé: | Universidad de Alicante. Departamento de Fisiología, Genética y Microbiología, Fisiología de Membranas |
| Rok vydání: | 2019 |
| Předmět: |
Anions
Models Molecular Patch-Clamp Techniques Potassium Channels Lipid Bilayers KcsA potassium channel Biophysics Arginine Fisiología Polymorphism Single Nucleotide Biochemistry 03 medical and health sciences Molecular dynamics chemistry.chemical_compound Membrane Lipids Reaction rate constant Bacterial Proteins Patch-clamp recordings medicine Phospholipids 030304 developmental biology Alanine 0303 health sciences Binding Sites Ion channel inactivation Chemistry Molecular dynamics simulations 030302 biochemistry & molecular biology Triad (anatomy) Phosphatidylglycerols Phosphatidic acid Cell Biology Potassium channel Kinetics Membrane medicine.anatomical_structure Ion channel kinetics Membrane lipid-protein interactions Potassium Channels Voltage-Gated Mutation Streptomyces lividans Ion Channel Gating Protein Binding |
| Zdroj: | RUA. Repositorio Institucional de la Universidad de Alicante Universidad de Alicante (UA) Poveda, J A, Giudici, A M, Renart, M L, Millet, O, Morales, A, González-Ros, J M, Oakes, V, Furini, S & Domene, C 2019, ' Modulation of the potassium channel KcsA by anionic phospholipids : Role of arginines at the non-annular lipid binding sites ', Biochimica Et Biophysica Acta-Biomembranes, vol. 1861, no. 10, 183029 . https://doi.org/10.1016/j.bbamem.2019.183029 |
| Popis: | The role of arginines R64 and R89 at non-annular lipid binding sites of KcsA, on the modulation of channel activity by anionic lipids has been investigated. In wild-type (WT) KcsA reconstituted into asolectin lipid membranes, addition of phosphatidic acid (PA) drastically reduces inactivation in macroscopic current recordings. Consistent to this, PA increases current amplitude, mean open time and open probability at the single channel level. Moreover, kinetic analysis reveals that addition of PA causes longer open channel lifetimes and decreased closing rate constants. Effects akin to those of PA on WT-KcsA are observed when R64 and/or R89 are mutated to alanine, regardless of the added anionic lipids. We interpret these results as a consequence of interactions between the arginines and the anionic PA bound to the non-annular sites. NMR data shows indeed that at least R64 is involved in binding PA. Moreover, molecular dynamics (MD) simulations predict that R64, R89 and surrounding residues such as T61, mediate persistent binding of PA to the non-annular sites. Channel inactivation depends on interactions within the inactivation triad (E71-D80-W67) behind the selectivity filter. Therefore, it is expected that such interactions are affected when PA binds the arginines at the non-annular sites. In support of this, MD simulations reveal that PA binding prevents interaction between R89 and D80, which seems critical to the effectiveness of the inactivation triad. This mechanism depends on the stability of the bound lipid, favoring anionic headgroups such as that of PA, which thrive on the positive charge of the arginines. This work was partly supported by grants PGC2018-093505-B-100, BFU2012-31359 and BFU2015-66612-P from the Spanish MINECO/FEDER (UE), and by BBSRC and Pfizer (BB/L015269/1) through a studentship to V. Oakes. |
| Databáze: | OpenAIRE |
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