Chloride and proton transport in bacteriorhodopsin mutant D85T: different modes of ion translocation in a retinal protein 1 1Edited by A.R.Fersht

Tittor, Jörg; Haupts, Ulrich; Haupts, Christina; Oesterhelt, Dieter; Becker, A.; Bamberg, Ernst

doi:10.1006/jmbi.1997.1204

Cited by 74 publications

(94 citation statements)

References 56 publications

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“…The transient sequestration of positively charged proton from the center of the ion-conducting pathway reduces the energy barrier for cation transport, and thereby facilitates sodium transfer (Fig. 4C) À pump simply by mutating single aspartate residue to threonine (D85T) [46,47]. Furthermore, recent studies have also shown that the Cl À pump can be converted into a proton pump, and the Na þ pump can be converted into a proton or Cl À pump by introducing 1-4 mutations, including those to the homologs of Asp85 and Thr89 in HsBR [48,49].…”

Section: The Schiff Base Region Is the Most Important Region Determinmentioning

confidence: 99%

The light‐driven sodium ion pump: A new player in rhodopsin research

Kato

Inoue

Kandori³

et al. 2016

BioEssays

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Rhodopsins are one of the most studied photoreceptor protein families, and ion-translocating rhodopsins, both pumps and channels, have recently attracted broad attention because of the development of optogenetics. Recently, a new functional class of ion-pumping rhodopsins, an outward Na þ pump, was discovered, and following structural and functional studies enable us to compare three functionally different ion-pumping rhodopsins: outward proton pump, inward Cl À pump, and outward Na þ pump. Here, we review the current knowledge on structure-function relationships in these three light-driven pumps, mainly focusing on Na þ pumps. A structural and functional comparison reveals both unique and conserved features of these ion pumps, and enhances our understanding about how the structurally similar microbial rhodopsins acquired such diverse functions. We also discuss some unresolved questions and future perspectives in research of ion-pumping rhodopsins, including optogenetics application and engineering of novel rhodopsins.

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Section: The Schiff Base Region Is the Most Important Region Determinmentioning

confidence: 99%

The light‐driven sodium ion pump: A new player in rhodopsin research

Kato

Inoue

Kandori³

et al. 2016

BioEssays

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“…This photocycle is used to generate a proton gradient that is used to drive membrane-bound ATPase to synthesize adenosine triphosphate (ATP) under anaerobic conditions [55][56][57]. After decades of research, the photocyclic mechanism of proton pumping of BR is well characterized and several models have been generated to help describe the complex nature of the BR photocycle [58][59][60][61][62][63].…”

Section: Bacteriorhodopsinmentioning

confidence: 99%

Directed evolution of bacteriorhodopsin for applications in bioelectronics

Wagner

Greco

Ranaghan

et al. 2013

J. R. Soc. Interface.

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In nature, biological systems gradually evolve through complex, algorithmic processes involving mutation and differential selection. Evolution has optimized biological macromolecules for a variety of functions to provide a comparative advantage. However, nature does not optimize molecules for use in human-made devices, as it would gain no survival advantage in such cooperation. Recent advancements in genetic engineering, most notably directed evolution, have allowed for the stepwise manipulation of the properties of living organisms, promoting the expansion of protein-based devices in nanotechnology. In this review, we highlight the use of directed evolution to optimize photoactive proteins, with an emphasis on bacteriorhodopsin (BR), for device applications. BR, a highly stable light-activated proton pump, has shown great promise in three-dimensional optical memories, real-time holographic processors and artificial retinas.

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“…A single point mutation, changing D85 to either threonine or serine, converts wild-type bacteriorhodopsin (bR) from what is commonly thought of as a proton pump into an anion pump shown to bind and pump a relatively broad range of substrates including chloride, bromide, and nitrate (1)(2)(3).…”

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confidence: 99%

Specificity of Anion Binding in the Substrate Pocket of Bacteriorhodopsin

et al. 2004

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The structure of the D85S mutant of bacteriorhodopsin with a nitrate anion bound in the Schiff base binding site and the structure of the anion-free protein have been obtained in the same crystal form. Together with the previously solved structures of this anion pump, in both the anion-free state and bromide-bound state, these new structures provide insight into how this mutant of bacteriorhodopsin is able to bind a variety of different anions in the same binding pocket. The structural analysis reveals that the main structural change that accommodates different anions is the repositioning of the polar side chain of S85. On the basis of these X-ray crystal structures, the prediction is then made that the D85S/D212N double mutant might bind similar anions and do so over a broader pH range than does the single mutant. Experimental comparison of the dissociation constants, K d, for a variety of anions confirms this prediction and demonstrates, in addition, that the binding affinity is dramatically improved by the D212N substitution.

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Chloride and proton transport in bacteriorhodopsin mutant D85T: different modes of ion translocation in a retinal protein 1 1Edited by A.R.Fersht

Cited by 74 publications

References 56 publications

The light‐driven sodium ion pump: A new player in rhodopsin research

The light‐driven sodium ion pump: A new player in rhodopsin research

Directed evolution of bacteriorhodopsin for applications in bioelectronics

Specificity of Anion Binding in the Substrate Pocket of Bacteriorhodopsin

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