Mechanism of Ion Transport across Membranes

Lanyi, Janos Κ.

doi:10.1074/jbc.272.50.31209

Cited by 191 publications

(98 citation statements)

References 83 publications

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“…L- [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] O]threonine was synthesized as described (25). [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] O]threonine-labeled BR was prepared by growing Halobacterium salinarum (JW-3) in a defined medium similar to that described by Gochnauer and Kushner (26), except that the D-amino acids and NH 4 Cl were omitted and the L-threonine was replaced by 0.25 g͞liter L- [3-18 O]threonine. Under these conditions, lipid extraction and amino acid analysis with radiotracers show that typically about two-thirds of the threonine residues are labeled, with no scrambling of the label (27).…”

Section: Methodsmentioning

confidence: 99%

“…Fig. 3d measured at 53.5°clearly shows that a peak pair at 3,415 (ϩ) and 3,402 (Ϫ) cm Ϫ1 of unlabeled BR (dotted line) has a downshift to 3,399 (ϩ) and 3,387 (Ϫ) cm Ϫ1 , respectively, in the measurement of [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] O]threonine-labeled BR (solid line).…”

Section: Assignment Of the O-h And O-d Stretch Bands To Threonine Sidementioning

confidence: 99%

“…Absorption of light triggers a cyclic reaction that comprises a series of intermediates, designated as the J, K, KL, L, M, N, and O states (1)(2)(3)(4). Protein structural changes in these intermediate states cause proton translocation across the protein, and their mechanism is the central question in current studies of BR (14).…”

Section: B Acteriorhodopsin (Br) Is a Light-driven Proton Pump Inmentioning

confidence: 99%

“…For the present study, we prepared [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] O]threonine-labeled BR and used polarized FTIR spectroscopy to investigate the possible involvement of hydrogen-bonding alterations in the photoisomerization of the retinal chromophore. As a result of the accurate detection that we have developed throughout the mid-IR region (23), we found that three threonines change their hydrogen bonding.…”

Section: B Acteriorhodopsin (Br) Is a Light-driven Proton Pump Inmentioning

confidence: 99%

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Local and distant protein structural changes on photoisomerization of the retinal in bacteriorhodopsin

Kandori

Kinoshita

Yamazaki

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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The photoisomerization of the retinal in bacteriorhodopsin is selective and efficient and yields perturbation of the protein structure within femtoseconds. The stored light energy in the primary intermediate is then used for the net translocation of a proton across the membrane in the microsecond to millisecond regime. This study is aimed at identifying how the protein changes on photoisomerization by using the O-H groups of threonines as internal probes. Polarized Fourier-transform IR spectroscopy of [3-18 O]threonine-labeled and unlabeled bacteriorhodopsin indicates that 3 of the threonines (of a total of 18) change their hydrogen bonding. One is exchangeable in D 2O, but two are not. A comprehensive mutation study indicates that the residues involved are Thr-89, Thr-17, and Thr-121 (or Thr-90). The perturbation of only three threonine side chains suggests that the structural alteration at this stage of the photocycle is local and specific. Furthermore, the structural change of Thr-17, which is located >11 Å from the retinal chromophore, implicates a specific perturbation channel in the protein that accompanies the retinal motion. B acteriorhodopsin (BR) is a light-driven proton pump inHalobacterium salinarum that contains all-trans retinal as chromophore (1-4). Its tertiary structure has been determined recently by cryoelectron microscopy (5-7) and x-ray crystallography (8-13). The retinal binds covalently to Lys-216 through a protonated Schiff base linkage. Absorption of light triggers a cyclic reaction that comprises a series of intermediates, designated as the J, K, KL, L, M, N, and O states (1-4). Protein structural changes in these intermediate states cause proton translocation across the protein, and their mechanism is the central question in current studies of BR (14).The all-trans to 13-cis photoisomerization leads to the formation of the primary K intermediate (15)(16)(17). It is well known that photoisomerization in BR is highly selective and efficient. In solution, the photoproduct of all-trans retinal with protonated Schiff base is mainly 11-cis [82% (vol/vol) 11-cis͞6% (vol/vol) 13-cis͞12% (vol/vol) 9-cis in methanol; ref. 18], whereas in BR, the photoproduct is 100% (vol͞vol) 13-cis. The quantum efficiency for isomerization in BR (Ϸ0.6; refs. 19 and 20) is much higher than for retinal in solution (0.13 in methanol; ref. 18). This efficiency is correlated closely with the rate constant of the isomerization, because it occurs on the femtosecond time scale. The protein environment thus certainly facilitates the specificity of the reaction of the retinal chromophore.How does the highly selective and efficient isomerization occur in BR? How does the protein respond to the chromophore motion? To address these questions, structural analysis of the primary intermediates is essential. Cryoelectron microscopy of the K intermediate reported that the structural change at this stage is not resolved with 3.5-Å resolution (21). More recent analysis of the K intermediate by x-ray crystallography identified few...

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Section: Methodsmentioning

confidence: 99%

Section: Assignment Of the O-h And O-d Stretch Bands To Threonine Sidementioning

confidence: 99%

Section: B Acteriorhodopsin (Br) Is a Light-driven Proton Pump Inmentioning

confidence: 99%

Section: B Acteriorhodopsin (Br) Is a Light-driven Proton Pump Inmentioning

confidence: 99%

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Local and distant protein structural changes on photoisomerization of the retinal in bacteriorhodopsin

Kandori

Kinoshita

Yamazaki

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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“…ered to be a prototype for a membrane transporter (4) and also serves as a structure model for G-protein-coupled receptors. BR and G-protein-coupled receptors share in common a seven-helix topology, and both are thought to operate by a similar switching mechanism (5-7).…”

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confidence: 99%

Spatial Organization of Bacteriorhodopsin in Model Membranes

Kahya

Wiersma

Poolman

et al. 2002

Journal of Biological Chemistry

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Bacteriorhodopsin is a proton-transporting membrane protein in Halophilic archaea, and it is considered a prototype of membrane transporters and a model for G-protein-coupled receptors. Oligomerization of the protein has been reported, but it is unknown whether this feature is correlated with, for instance, light activation. Here, we have addressed this issue by reconstituting bacteriorhodopsin into giant unilamellar vesicles. The dynamics of the fully active protein was investigated using fluorescence correlation spectroscopy and freeze fracture electron microscopy. At low protein-tolipid ratios (<1:10 w/w), a decrease in mobility was observed upon protein photoactivation. This process occurred on a second time scale and was fully reversible, i.e. when the dark-adapted state was reestablished the lateral diffusion rate of the protein was returned to that prior to activation. A similar decrease in lateral mobility as observed upon photoactivation was obtained when bacteriorhodopsin was reconstituted at high protein-tolipid ratios (>1:10 w/w). We interpret the shifts in mobility during light adaptation as being caused by transient photoinduced oligomerization of bacteriorhodopsin. These observations are fully supported by freeze-fracture electron microscopy, and the size of the clusters during photoactivation was estimated to consist of two or three trimers.

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Plasma‐MembraneH⁺‐ATPaseFrom Yeast

Lecchi

Slayman

2008

Protein Science Encyclopedia

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Originally published in: Handbook of ATPase. Edited by Masamitsu Futai, Yoh Wada and Jack H. Kaplan. Copyright © 2004 Wiley‐VCH Verlag GmbH & Co. KGaA Weinheim. Print ISBN: 3‐527‐30689‐3 The sections in this article are Introduction Structure Ca 2+ ‐ ATPase as a Model Applicability of the Ca 2+ ‐ ATPase Structure to Other P 2 ‐ ATPase , Including the Pma1 H + ‐ ATPase H + ‐ ATPase Oligomers Associated Proteolipids Reaction Mechanism Overview of the Reaction Cycle ATP Binding and Phosphorylation E1–E2 Conformational Change H + Pumping Biogenesis Pma1 Mutants with Defects in Folding and Biogenesis Use of Pma1 Mutants to Screen for Other Genes that Play a Role in Biogenesis and Quality Control Role of Lipid Rafts Regulation Emerging Knowledge of Other Yeast P‐type ATPase Acknowledgments

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Mechanism of Ion Transport across Membranes

Cited by 191 publications

References 83 publications

Local and distant protein structural changes on photoisomerization of the retinal in bacteriorhodopsin

Local and distant protein structural changes on photoisomerization of the retinal in bacteriorhodopsin

Spatial Organization of Bacteriorhodopsin in Model Membranes

Plasma‐MembraneH⁺‐ATPaseFrom Yeast

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Mechanism of Ion Transport across Membranes

Cited by 191 publications

References 83 publications

Local and distant protein structural changes on photoisomerization of the retinal in bacteriorhodopsin

Local and distant protein structural changes on photoisomerization of the retinal in bacteriorhodopsin

Spatial Organization of Bacteriorhodopsin in Model Membranes

Plasma‐MembraneH+‐ATPaseFrom Yeast

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Product

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Plasma‐MembraneH⁺‐ATPaseFrom Yeast