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Lefoulon C, Karnik R, Honsbein A, Gutla PV, Grefen C, Riedelsberger J, Poblete T, Dreyer I, Gonzalez W, Blatt MR. Voltage-sensor transitions of the inward-rectifying K+ channel KAT1 indicate a latching mechanism biased by hydration within the voltage sensor. PLANT PHYSIOLOGY 2014; 166:960-75. [PMID: 25185120 PMCID: PMC4213121 DOI: 10.1104/pp.114.244319] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The Kv-like (potassium voltage-dependent) K(+) channels at the plasma membrane, including the inward-rectifying KAT1 K(+) channel of Arabidopsis (Arabidopsis thaliana), are important targets for manipulating K(+) homeostasis in plants. Gating modification, especially, has been identified as a promising means by which to engineer plants with improved characteristics in mineral and water use. Understanding plant K(+) channel gating poses several challenges, despite many similarities to that of mammalian Kv and Shaker channel models. We have used site-directed mutagenesis to explore residues that are thought to form two electrostatic countercharge centers on either side of a conserved phenylalanine (Phe) residue within the S2 and S3 α-helices of the voltage sensor domain (VSD) of Kv channels. Consistent with molecular dynamic simulations of KAT1, we show that the voltage dependence of the channel gate is highly sensitive to manipulations affecting these residues. Mutations of the central Phe residue favored the closed KAT1 channel, whereas mutations affecting the countercharge centers favored the open channel. Modeling of the macroscopic current kinetics also highlighted a substantial difference between the two sets of mutations. We interpret these findings in the context of the effects on hydration of amino acid residues within the VSD and with an inherent bias of the VSD, when hydrated around a central Phe residue, to the closed state of the channel.
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Affiliation(s)
- Cécile Lefoulon
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
| | - Rucha Karnik
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
| | - Annegret Honsbein
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
| | - Paul Vijay Gutla
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
| | - Christopher Grefen
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
| | - Janin Riedelsberger
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
| | - Tomás Poblete
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
| | - Ingo Dreyer
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
| | - Wendy Gonzalez
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom (C.L., R.K., A.H., P.V.G., C.G., M.R.B.);Centro de Bioinformatica y Simulacion Molecular, Universidad de Talca, Casilla 721, Talca, Chile (J.R., T.P., W.G.);University of Potsdam, Biochemistry and Biology Group BPMBP, D14476 Golm, Germany (J.R., I.D., W.G.); andCentre for Biotechnology and Plant Genomics UPM, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, 28223 Pozuelo de Alacon, Madrid, Spain (I.D.)
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Lupieri P, Ippoliti E, Altoè P, Garavelli M, Mwalaba M, Carloni P. Spectroscopic Properties of Formaldehyde in Aqueous Solution: Insights from Car−Parrinello and TDDFT/CASPT2 Calculations. J Chem Theory Comput 2010; 6:3403-9. [DOI: 10.1021/ct100384f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Paola Lupieri
- German Research School for Simulation Sciences GmbH, 52425 Jülich and RWTH Aachen, Germany, SISSA, via Bonomea 265, 34136 Trieste, Italy, Department of Chemistry “G. Ciamician”, University of Bologna, via Selmi 2, I-40126 Bologna, Italy, International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy, and Democritos Modeling Center for Research in Atomistic Simulation, via Bonomea 265, 34136 Trieste, Italy
| | - Emiliano Ippoliti
- German Research School for Simulation Sciences GmbH, 52425 Jülich and RWTH Aachen, Germany, SISSA, via Bonomea 265, 34136 Trieste, Italy, Department of Chemistry “G. Ciamician”, University of Bologna, via Selmi 2, I-40126 Bologna, Italy, International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy, and Democritos Modeling Center for Research in Atomistic Simulation, via Bonomea 265, 34136 Trieste, Italy
| | - Piero Altoè
- German Research School for Simulation Sciences GmbH, 52425 Jülich and RWTH Aachen, Germany, SISSA, via Bonomea 265, 34136 Trieste, Italy, Department of Chemistry “G. Ciamician”, University of Bologna, via Selmi 2, I-40126 Bologna, Italy, International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy, and Democritos Modeling Center for Research in Atomistic Simulation, via Bonomea 265, 34136 Trieste, Italy
| | - Marco Garavelli
- German Research School for Simulation Sciences GmbH, 52425 Jülich and RWTH Aachen, Germany, SISSA, via Bonomea 265, 34136 Trieste, Italy, Department of Chemistry “G. Ciamician”, University of Bologna, via Selmi 2, I-40126 Bologna, Italy, International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy, and Democritos Modeling Center for Research in Atomistic Simulation, via Bonomea 265, 34136 Trieste, Italy
| | - M. Mwalaba
- German Research School for Simulation Sciences GmbH, 52425 Jülich and RWTH Aachen, Germany, SISSA, via Bonomea 265, 34136 Trieste, Italy, Department of Chemistry “G. Ciamician”, University of Bologna, via Selmi 2, I-40126 Bologna, Italy, International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy, and Democritos Modeling Center for Research in Atomistic Simulation, via Bonomea 265, 34136 Trieste, Italy
| | - Paolo Carloni
- German Research School for Simulation Sciences GmbH, 52425 Jülich and RWTH Aachen, Germany, SISSA, via Bonomea 265, 34136 Trieste, Italy, Department of Chemistry “G. Ciamician”, University of Bologna, via Selmi 2, I-40126 Bologna, Italy, International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy, and Democritos Modeling Center for Research in Atomistic Simulation, via Bonomea 265, 34136 Trieste, Italy
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