Bioinformatic and Mutational Analysis of Channelrhodopsin-2 Protein Cation-conducting Pathway

Plazzo, Anna Pia; Franceschi, Nicola De; Broi, Francesca Da; Zonta, Francesco; Sanasi, Maria Federica; Filippini, F.; Mongillo, Marco

doi:10.1074/jbc.m111.326207

Cited by 34 publications

(43 citation statements)

References 43 publications

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“…Replacement of E3 [hydrogen-bonded to Ser 63 and Asn 258 forming the central gate (86, 87); ChR2 residue numbering] had the largest impact. Replacement of inner-gate His 134 /E2 or access-channel E4/E5 also reduced H conductance (62, 64, 88, 89). Further support for this proton-wire hypothesis is derived from cryptophyte anion-conducting ChRs (90), which show reduced H + conductance with fewer helix-2 glutamates (90); interestingly, these glutamates have little influence on kinetics, and only mutation of E1 decelerates closing (88, 91).…”

Section: Selectivity Variantsmentioning

confidence: 98%

The form and function of channelrhodopsin

Deisseroth

Hegemann

2017

Science

232

214

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Channelrhodopsins are light-gated ion channels that, via regulation of flagellar function, enable single-celled motile algae to seek ambient light conditions suitable for photosynthesis and survival. These plant behavioral responses were initially investigated more than 150 years ago. Recently, major principles of function for light-gated ion channels have been elucidated by creating channelrhodopsins with kinetics that are accelerated or slowed over orders of magnitude, by discovering and designing channelrhodopsins with altered spectral properties, by solving the high-resolution channelrhodopsin crystal structure, and by structural model–guided redesign of channelrhodopsins for altered ion selectivity. Each of these discoveries not only revealed basic principles governing the operation of light-gated ion channels, but also enabled the creation of new proteins for illuminating, via optogenetics, the fundamentals of brain function.

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Section: Selectivity Variantsmentioning

confidence: 98%

The form and function of channelrhodopsin

Deisseroth

Hegemann

2017

Science

232

214

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“…In MD simulations, the hydrophilic pore attracts water from the extracellular bulk phase; this so-called access channel with a diameter of 8 Å is framed by side chains of polar residues including the essential R120 and the polar E4 and E5 (55,78). Near the RSBH + , the water distribution is discontinuous, and the channel is blocked by S63, E3, and N258, which are interconnected by several hydrogen bonds (referred to as the central gate, see Figure 1e) ( restriction site (referred to as the inner gate, see Figure 1d ) is given by Y70 in combination with the hydrophilic cluster of E1 and E2 and their hydrogen-bonding partners H134 and R268, which are located on H3 and H7, respectively.…”

Section: Ion Permeation Pathwaymentioning

confidence: 99%

“…Most importantly, ChR2 S63, E90, and N258 of the central gate (Figure 1e) are critical determinants. The introduction of a second negative charge into the central gate region, as, for example, in ChR2 S63D or N258D, favors the transport of divalent cations (31,55). Mutations of ChR2 E90 result in different ion selectivities depending on the character of the introduced residue.…”

Section: Putative Selectivity Filtermentioning

confidence: 99%

Biophysics of Channelrhodopsin

Schneider

Grimm²,

Hegemann

2015

Annu. Rev. Biophys.

175

166

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Channelrhodopsins (ChRs) are directly light-gated ion channels that function as sensory photoreceptors in flagellated green algae, allowing these algae to identify optimal light conditions for growth. In neuroscience, ChRs constitute the most versatile tools for the light-induced activation of selected cells or cell types with unprecedented precision in time and space. In recent years, many ChR variants have been discovered or engineered, and countless electrical and spectroscopic studies of these ChRs have been carried out, both in host cells and on purified recombinant proteins. With significant support from a high-resolution 3D structure and from molecular dynamics calculations, scientists are now able to develop models that conclusively explain ChR activation and ion conductance on the basis of chromophore isomerization, structural changes, proton transfer reactions, and water rearrangement on timescales ranging from femtoseconds to minutes.

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“…S1), implicated in control of ion selectivity in CrChR2 (63)(64)(65), and Ser-136, which regulates the size of the channel pore (66). Of three positively charged residues that form a vestibule on the extracellular side of the channel pore in C1C2 (43), Lys-154 is substituted with Val in PsChR.…”

Section: Namentioning

confidence: 99%

Characterization of a Highly Efficient Blue-shifted Channelrhodopsin from the Marine Alga Platymonas subcordiformis

Govorunova

Sineshchekov

et al. 2013

Journal of Biological Chemistry

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Background: Channelrhodopsins are algal phototaxis receptors used in optogenetics. Results: Channel activity and photochemistry of a new channelrhodopsin (PsChR) are characterized. Conclusion: Blue-shifted PsChR has ϳ3-fold greater unitary conductance, faster recovery from excitation, and higher sodium selectivity than channelrhodopsin 2 from Chlamydomonas. Significance: These properties of PsChR facilitate further analysis of light-gated channel function and are potentially useful for optogenetics.

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Bioinformatic and Mutational Analysis of Channelrhodopsin-2 Protein Cation-conducting Pathway

Cited by 34 publications

References 43 publications

The form and function of channelrhodopsin

The form and function of channelrhodopsin

Biophysics of Channelrhodopsin

Characterization of a Highly Efficient Blue-shifted Channelrhodopsin from the Marine Alga Platymonas subcordiformis

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