Visual Pigments and Bacteriorhodopsins Formed From Aromatic Retinal Analogs

Derguini, Fadila; Bigge, Christopher F.; Croteau, Allan A.; Balogh‐Nair, Valeria; Nakanishi, K.

doi:10.1111/j.1751-1097.1984.tb03906.x

Cited by 12 publications

(9 citation statements)

References 40 publications

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“…Phenyl-retinal A1 was previously reported to react very slowly with bacterio-opsin, yielding a strongly blue-shifted analogue pigment [31,32]. In the case of the bacterial opsins, phenylretinal A1 behaves quite differently from the other two analogues.…”

Section: Analogue Pigmentsmentioning

confidence: 98%

“…Phenyl-retinal A1 contains an even more complex conjugated system, but lacks the methyl groups in the ring element. This analogue blue-shifts the absorbance band of BR [31,32] and probably of XR as well [30,33]. In 6-strans-locked retinal A1, the C6-C7 bond is locked in an s-trans configuration.…”

Section: Modulation Of Spectral Properties and Pump Activity Of Proteorhodopsins By Retinal Analogues Introductionmentioning

confidence: 96%

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Modulation of spectral properties and pump activity of proteorhodopsins by retinal analogues

Ganapathy

Bécheau

Venselaar³

et al. 2015

Biochemical Journal

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Proteorhodopsins are heptahelical membrane proteins which function as light-driven proton pumps. They use all-trans-retinal A1 as a ligand and chromophore and absorb visible light (520-540 nm). In the present paper, we describe modulation of the absorbance band of the proteorhodopsin from Monterey Bay SAR 86 gammaproteobacteria (PR), its red-shifted double mutant PR-D212N/F234S (PR-DNFS) and Gloeobacter rhodopsin (GR). This was approached using three analogues of all-trans-retinal A1, which differ in their electronic and conformational properties: all-trans-6,7-s-trans-locked retinal A1, all-trans-phenyl-retinal A1 and all-trans-retinal A2. We further probed the effect of these retinal analogues on the proton pump activity of the proteorhodopsins. Our results indicate that, whereas the constraints of the retinal-binding pocket differ for the proteorhodopsins, at least two of the retinal analogues are capable of shifting the absorbance bands of the pigments either bathochromically or hypsochromically, while maintaining their proton pump activity. Furthermore, the shifts implemented by the analogues add up to the shift induced by the double mutation in PR-DNFS. This type of chromophore substitution may present attractive applications in the field of optogenetics, towards increasing the flexibility of optogenetic tools or for membrane potential probes.

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Section: Analogue Pigmentsmentioning

confidence: 98%

Section: Modulation Of Spectral Properties and Pump Activity Of Proteorhodopsins By Retinal Analogues Introductionmentioning

confidence: 96%

Modulation of spectral properties and pump activity of proteorhodopsins by retinal analogues

Ganapathy

Bécheau

Venselaar³

et al. 2015

Biochemical Journal

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“…(e) The retinal is substituted with phenyland indene retinals (63). The small single aromatic ring ofphenol is less conjugated than the naphthalene ring in naphthylretinal and, therefore, less planar.…”

Section: Exciton Model Of the Pmmentioning

confidence: 99%

Unique biphasic band shape of the visible circular dichroism of bacteriorhodopsin in purple membrane

Cassim

1992

Biophysical Journal

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OVER A DECADE AND A HALF AGO, WHEN THE FIRST VISIBLE MEMBRANE SUSPENSION CIRCULAR DICHROIC (CD) SPECTRUM OF THE PURPLE MEMBRANE (PM) WAS PRESENTED, TWO MECHANISMS WERE PROPOSED TO ACCOUNT FOR THE OBSERVED BIPHASIC SHAPED CD BAND: (a) excitonic interactions among the retinals of the sole protein bacteriorhodopsin (bR) in the crystalline structure of the PM, and (b) combination of CD bands with opposite rotational strengths due to a retinal-apoprotein heterogeneity of the bR molecules or due to two possible close-lying long-wavelength transitions of the retinal of the bR with opposite rotational strengths. Since that time, an impressive body of experimental and theoretical evidence has been accumulated, mostly consistent with an exciton model but many at serious odds with any heterogeneity or multiple transition model. Recently, a number of articles have appeared reporting analyses of new experimental observations which are proposed to cast serious doubts on the viability of the exciton model, and therefore, may revive the heterogeneity or multiple transition model as an explanation for the unique shape of the CD band of the PM. The intent of this article is to demonstrate that if all observations found in literature baring on this question are considered in toto and in a consistent manner, they can be interpreted without exception by excitons, and furthermore, that there is no plausible evidence available to warrant the revival of the heterogeneity or multiple transition model as an explanation for the unique shape of the biphasic CD band of the PM.

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“…Surprisingly, as well, BR, which has a set of residues lining the binding pocket identical to AR3 (Fig. , Table ), was reported to slowly bind PHE, yielding a stable, blueshifted pigment, when expressed in its native environment . Hence, we surmise that, upon expression in E. coli , AR3 can only bind its ligand while still in its folding stage.…”

Section: Resultsmentioning

confidence: 82%

Redshifted and Near‐infrared Active Analog Pigments Based upon Archaerhodopsin‐3

Ganapathy

Kratz

Chen

et al. 2019

Photochem & Photobiology

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Archaerhodopsin-3 (AR3) is a member of the microbial rhodopsin family of hepta-helical transmembrane proteins, containing a covalently bound molecule of all-trans retinal as a chromophore. It displays an absorbance band in the visible region of the solar spectrum (kmax 556 nm) and functions as a light-driven proton pump in the archaeon Halorubrum sodomense. AR3 and its mutants are widely used in neuroscience as optogenetic neural silencers and in particular as fluorescent indicators of transmembrane potential. In this study, we investigated the effect of analogs of the native ligand all-trans retinal A1 on the spectral properties and proton-pumping activity of AR3 and its single mutant AR3 (F229S). While, surprisingly, the 3-methoxyretinal A2 analog did not redshift the absorbance maximum of AR3, the analogs retinal A2 and 3-methylamino-16-nor-1,2,3,4-didehydroretinal (MMAR) did generate active redshifted AR3 pigments. The MMAR analog pigments could even be activated by near-infrared light. Furthermore, the MMAR pigments showed strongly enhanced fluorescence with an emission band in the near-infrared peaking around 815 nm. We anticipate that the AR3 pigments generated in this study have widespread potential for near-infrared exploitation as fluorescent voltage-gated sensors in optogenetics and artificial leafs and as proton pumps in bioenergy-based applications.

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Visual Pigments and Bacteriorhodopsins Formed From Aromatic Retinal Analogs

Cited by 12 publications

References 40 publications

Modulation of spectral properties and pump activity of proteorhodopsins by retinal analogues

Modulation of spectral properties and pump activity of proteorhodopsins by retinal analogues

Unique biphasic band shape of the visible circular dichroism of bacteriorhodopsin in purple membrane

Redshifted and Near‐infrared Active Analog Pigments Based upon Archaerhodopsin‐3

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