Dynamics and mechanism of a light-driven chloride pump

Mous, S.; Gotthard, Guillaume; Ehrenberg, D.; Sen, Saumik; Weinert, T.; Johnson, Philip J. M.; James, Daniel; Nass, Karol; Furrer, Antonia; Kekilli, D.; Ma, Pikyee; Brünle, Steffen; Casadei, Cecilia M.; Martiel, Isabelle; Dworkowski, Florian; Gashi, Dardan; Skopintsev, Petr; Wranik, Maximilian; Knopp, G.; Panepucci, Ezequiel; Panneels, Valérie; Cirelli, Claudio; Ozerov, Dmitry; Schertler, G.F.X.; Wang, Meitian; Milne, Chris; Standfuss, Joerg; Schapiro, Igor; Heberle, Joachim; Nogly, Przemyslaw

doi:10.1126/science.abj6663

Cited by 64 publications

(47 citation statements)

References 76 publications

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“…It may further remain an acceptable approximation for larger structural changes in which a substantial number of atoms in the unit cell are involved, provided that the isomorphism between the two dataset remains high 5 (e.g., ref. 6 ). The information content of Fourier difference maps can be improved by Bayesian-statistics weighting of structure factor amplitude (SFA) differences 7 , 8 , yet these maps can be featureless when structural changes or the triggered-state occupancy are small, or if a mixture of triggered states accumulates 9 , whose overlaying positive and negative difference peaks cancel each other.…”

Section: Introductionmentioning

confidence: 99%

Xtrapol8 enables automatic elucidation of low-occupancy intermediate-states in crystallographic studies

et al. 2022

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Unstable states studied in kinetic, time-resolved and ligand-based crystallography are often characterized by a low occupancy, which hinders structure determination by conventional methods. To automatically extract structural information pertaining to these states, we developed Xtrapol8, a program which (i) applies various flavors of Bayesian-statistics weighting to generate the most informative Fourier difference maps; (ii) determines the occupancy of the intermediate states by use of methods hitherto not available; (iii) calculates extrapolated structure factors using the various proposed formalisms while handling the issue of negative structure factor amplitudes, and (iv) refines the corresponding structures in real and reciprocal-space. The use of Xtrapol8 could accelerate data processing in kinetic and time-resolved crystallographic studies, and as well foster the identification of drug-targetable states in ligand-based crystallography.

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Section: Introductionmentioning

confidence: 99%

Xtrapol8 enables automatic elucidation of low-occupancy intermediate-states in crystallographic studies

et al. 2022

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“…Thereby, kinetic information is retrieved on the temporal sequence of structural changes in mechanosensitive channels. Time-resolved crystallographic techniques can track these structural changes at utmost temporal and spatial resolution ( Skopintsev et al, 2020 ; Mous et al, 2022 ), once the mechanosensing protein is co-crystalized with AzoPC. Finally, these experiments will derive an atomic picture of the lipid/protein coupling and resolve the gating mechanism of these channels.…”

Section: Discussionmentioning

confidence: 99%

Photoactivation of a Mechanosensitive Channel

Crea

Vorkas

Redlich

et al. 2022

Front. Mol. Biosci.

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Optogenetics in the conventional sense, i.e. the use of engineered proteins that gain their light sensitivity from naturally abundant chromophores, represents an exciting means to trigger and control biological activity by light. As an alternate approach, photopharmacology controls biological activity with the help of synthetic photoswitches. Here, we used an azobenzene-derived lipid analogue to optically activate the transmembrane mechanosensitive channel MscL which responds to changes in the lateral pressure of the lipid bilayer. In this work, MscL has been reconstituted in nanodiscs, which provide a native-like environment to the protein and a physical constraint to membrane expansion. We characterized this photomechanical system by FTIR spectroscopy and assigned the vibrational bands of the light-induced FTIR difference spectra of the trans and cis states of the azobenzene photolipid by DFT calculations. Differences in the amide I range indicated reversible conformational changes in MscL as a direct consequence of light switching. With the mediation of nanodiscs, we inserted the transmembrane protein in a free standing photoswitchable lipid bilayer, where electrophysiological recordings confirmed that the ion channel could be set to one of its sub-conducting states upon light illumination. In conclusion, a novel approach is presented to photoactivate and control cellular processes as complex and intricate as gravitropism and turgor sensing in plants, contractility of the heart, as well as sensing pain, hearing, and touch in animals.

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“…Following chromophore isomerization the chloride ion first dissociates from the protonated Schiff base and then starts to diffuse away. Additional molecular details of the interactions and trajectory of the chloride ion are provided by recent ps up to ms studies using time-resolved serial crystallography in combination with spectral and theoretical analysis ( Hosaka et al, 2022 ; Mous et al, 2022 ). An XFEL study of the channelrhodopsin chimera C1C2, that photochemically behaves like ChR1, investigated the photo-induced conformational changes from 1 µs to 4 ms ( Oda et al, 2021 ).…”

Section: Photochemical Propertiesmentioning

confidence: 99%

Rhodopsins: An Excitingly Versatile Protein Species for Research, Development and Creative Engineering

Grip

Ganapathy

2022

Front. Chem.

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The first member and eponym of the rhodopsin family was identified in the 1930s as the visual pigment of the rod photoreceptor cell in the animal retina. It was found to be a membrane protein, owing its photosensitivity to the presence of a covalently bound chromophoric group. This group, derived from vitamin A, was appropriately dubbed retinal. In the 1970s a microbial counterpart of this species was discovered in an archaeon, being a membrane protein also harbouring retinal as a chromophore, and named bacteriorhodopsin. Since their discovery a photogenic panorama unfolded, where up to date new members and subspecies with a variety of light-driven functionality have been added to this family. The animal branch, meanwhile categorized as type-2 rhodopsins, turned out to form a large subclass in the superfamily of G protein-coupled receptors and are essential to multiple elements of light-dependent animal sensory physiology. The microbial branch, the type-1 rhodopsins, largely function as light-driven ion pumps or channels, but also contain sensory-active and enzyme-sustaining subspecies. In this review we will follow the development of this exciting membrane protein panorama in a representative number of highlights and will present a prospect of their extraordinary future potential.

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Dynamics and mechanism of a light-driven chloride pump

Cited by 64 publications

References 76 publications

Xtrapol8 enables automatic elucidation of low-occupancy intermediate-states in crystallographic studies

Xtrapol8 enables automatic elucidation of low-occupancy intermediate-states in crystallographic studies

Photoactivation of a Mechanosensitive Channel

Rhodopsins: An Excitingly Versatile Protein Species for Research, Development and Creative Engineering

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