Role of the central arginine R133 toward the ion selectivity of the phosphate specific channel OprP: effects of charge and solvation
| Autor: | Iván Bárcena-Uribarri, Niraj Modi, Robert E. W. Hancock, Manjeet Bains, Ulrich Kleinekathöfer, Roland Benz |
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| Rok vydání: | 2013 |
| Předmět: |
Models
Molecular Inorganic chemistry Lipid Bilayers Molecular Sequence Data Porins Molecular Dynamics Simulation 010402 general chemistry Arginine 01 natural sciences Biochemistry Binding Competitive Ion Membrane Potentials Phosphates 03 medical and health sciences chemistry.chemical_compound Bacterial Proteins Amino Acid Sequence Ion transporter Binding selectivity 030304 developmental biology 0303 health sciences Binding Sites Ion Transport Sequence Homology Amino Acid Chemistry Bilayer Periplasmic space Phosphate 0104 chemical sciences Protein Structure Tertiary Solutions Porin Mutation Biophysics Selectivity Ion Channel Gating Bacterial Outer Membrane Proteins Protein Binding |
| Zdroj: | Biochemistry. 52(33) |
| ISSN: | 1520-4995 |
| Popis: | The outer membrane porin OprP of Pseudomonas aeruginosa forms a highly specific phosphate selective channel. This channel is responsible for the high-affinity uptake of phosphate ions into the periplasmic space of the bacteria. A detailed investigation of the structure-function relationship of OprP is inevitable to decipher the anion and phosphate selectivity of this porin in particular and to broaden the present understanding of the ion selectivity of different channels. To this end we investigated the role of the central arginine of OprP, R133, in terms of its effects in selectivity and ion transport properties of the pore. Electrophysiological bilayer measurements and free-energy molecular dynamics simulations were carried out to probe the transport of different ions through various R133 mutants. For these mutants, the change in phosphate binding specificity, ion conduction, and anion selectivity was determined and compared to previous molecular dynamic calculations and electrophysiological measurements with wild-type OprP. Molecular analysis revealed a rather particular role of arginine 133 and its charge, while at the same time this residue together with the network of other residues, namely, D94 and Y114, has the ability to dehydrate the permeating ion. These very specific features govern the ion selectivity of OprP. |
| Databáze: | OpenAIRE |
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