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Crystal Structures of the L(1), L(2), N, and O States of pharaonis Halorhodopsin

Halorhodopsin from Natronomonas pharaonis (pHR) functions as a light-driven halide ion pump. In the presence of halide ions, the photochemical reaction of pHR is described by the scheme: K→ L(1) → L(2) → N → O → pHR′ → pHR. Here, we report light-induced structural changes of the pHR-bromide complex...

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Autores principales: Kouyama, Tsutomu, Kawaguchi, Haruki, Nakanishi, Taichi, Kubo, Hiroki, Murakami, Midori
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Biophysical Society 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4457492/
https://www.ncbi.nlm.nih.gov/pubmed/26039169
http://dx.doi.org/10.1016/j.bpj.2015.04.027
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author Kouyama, Tsutomu
Kawaguchi, Haruki
Nakanishi, Taichi
Kubo, Hiroki
Murakami, Midori
author_facet Kouyama, Tsutomu
Kawaguchi, Haruki
Nakanishi, Taichi
Kubo, Hiroki
Murakami, Midori
author_sort Kouyama, Tsutomu
collection PubMed
description Halorhodopsin from Natronomonas pharaonis (pHR) functions as a light-driven halide ion pump. In the presence of halide ions, the photochemical reaction of pHR is described by the scheme: K→ L(1) → L(2) → N → O → pHR′ → pHR. Here, we report light-induced structural changes of the pHR-bromide complex observed in the C2 crystal. In the L(1)-to-L(2) transition, the bromide ion that initially exists in the extracellular vicinity of retinal moves across the retinal Schiff base. Upon the formation of the N state with a bromide ion bound to the cytoplasmic vicinity of the retinal Schiff base, the cytoplasmic half of helix F moves outward to create a water channel in the cytoplasmic interhelical space, whereas the extracellular half of helix C moves inward. During the transition from N to an N-like reaction state with retinal assuming the 13-cis/15-syn configuration, the translocated bromide ion is released into the cytoplasmic medium. Subsequently, helix F relaxes into its original conformation, generating the O state. Anion uptake from the extracellular side occurs when helix C relaxes into its original conformation. These structural data provide insight into the structural basis of unidirectional anion transport.
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spelling pubmed-44574922016-06-02 Crystal Structures of the L(1), L(2), N, and O States of pharaonis Halorhodopsin Kouyama, Tsutomu Kawaguchi, Haruki Nakanishi, Taichi Kubo, Hiroki Murakami, Midori Biophys J Membranes Halorhodopsin from Natronomonas pharaonis (pHR) functions as a light-driven halide ion pump. In the presence of halide ions, the photochemical reaction of pHR is described by the scheme: K→ L(1) → L(2) → N → O → pHR′ → pHR. Here, we report light-induced structural changes of the pHR-bromide complex observed in the C2 crystal. In the L(1)-to-L(2) transition, the bromide ion that initially exists in the extracellular vicinity of retinal moves across the retinal Schiff base. Upon the formation of the N state with a bromide ion bound to the cytoplasmic vicinity of the retinal Schiff base, the cytoplasmic half of helix F moves outward to create a water channel in the cytoplasmic interhelical space, whereas the extracellular half of helix C moves inward. During the transition from N to an N-like reaction state with retinal assuming the 13-cis/15-syn configuration, the translocated bromide ion is released into the cytoplasmic medium. Subsequently, helix F relaxes into its original conformation, generating the O state. Anion uptake from the extracellular side occurs when helix C relaxes into its original conformation. These structural data provide insight into the structural basis of unidirectional anion transport. The Biophysical Society 2015-06-02 /pmc/articles/PMC4457492/ /pubmed/26039169 http://dx.doi.org/10.1016/j.bpj.2015.04.027 Text en © 2015 The Authors http://creativecommons.org/licenses/by-nc-nd/3.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).
spellingShingle Membranes
Kouyama, Tsutomu
Kawaguchi, Haruki
Nakanishi, Taichi
Kubo, Hiroki
Murakami, Midori
Crystal Structures of the L(1), L(2), N, and O States of pharaonis Halorhodopsin
title Crystal Structures of the L(1), L(2), N, and O States of pharaonis Halorhodopsin
title_full Crystal Structures of the L(1), L(2), N, and O States of pharaonis Halorhodopsin
title_fullStr Crystal Structures of the L(1), L(2), N, and O States of pharaonis Halorhodopsin
title_full_unstemmed Crystal Structures of the L(1), L(2), N, and O States of pharaonis Halorhodopsin
title_short Crystal Structures of the L(1), L(2), N, and O States of pharaonis Halorhodopsin
title_sort crystal structures of the l(1), l(2), n, and o states of pharaonis halorhodopsin
topic Membranes
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4457492/
https://www.ncbi.nlm.nih.gov/pubmed/26039169
http://dx.doi.org/10.1016/j.bpj.2015.04.027
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