Color regulation in the archaebacterial phototaxis receptor phoborhodopsin (sensory rhodopsin II)

Takahashi, Tetsuo; Yan, Bing; Mazur, Paul; Derguini, Fadila; Nakanishi, Koji; Spudich, John L.

doi:10.1021/bi00488a038

Cited by 114 publications

(118 citation statements)

References 75 publications

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“…Acid induces a shift of 46 nm (Fig. 1), a larger shift than the 20 nm seen in GPR (5) and a loss of vibrational fine structure in the spectrum as observed for sensory rhodopsin II (19). The GPR spectral transition fits well to a single pK a of 7.2 ( Fig 2A); however, a second component is evident in the BPR titration according to hyperbolic fits to the data that yields a diprotic fit with pK a values 6.2 and 7.8 (Fig.…”

Section: Resultsmentioning

confidence: 77%

Spectroscopic and Photochemical Characterization of a Deep Ocean Proteorhodopsin

Wang

Sineshchekov

Spudich

et al. 2003

Journal of Biological Chemistry

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158

270

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A second group of proteorhodopsin-encoding genes (blue-absorbing proteorhodopsin, BPR) differing by 20 -30% in predicted primary structure from the first-discovered green-absorbing (GPR) group has been detected in picoplankton from Hawaiian deep sea water. Here we compare BPR and GPR absorption spectra, photochemical reactions, and proton transport activity. The photochemical reaction cycle of Hawaiian deep ocean BPR in cells is 10-fold slower than that of GPR with very low accumulation of a deprotonated Schiff base intermediate in cells and exhibits mechanistic differences, some of which are due to its glutamine residue rather than leucine at position 105. In contrast to GPR and other characterized microbial rhodopsins, spectral titrations of BPR indicate that a second titratable group, in addition to the retinylidene Schiff base counterion Asp-97, modulates the absorption spectrum near neutral pH. Mutant analysis confirms that Asp-97 and Glu-108 are proton acceptor and proton donor, respectively, in retinylidene Schiff base proton transfer reactions during the BPR photocycle as previously shown for GPR, but BPR contains an alternative acceptor evident in its D97N mutant, possibly the same as the second titratable group modulating the absorption spectrum. BPR, similar to GPR, carries out outward light-driven proton transport in Escherichia coli vesicles but with a reduced translocation rate attributable to its slower photocycle. In energized E. coli cells at physiological pH, the net effect of BPR photocycling is to generate proton currents dominated by a triggered proton influx, rather than efflux as observed with GPR-containing cells. Reversal of the proton current with the K ؉ -ionophore valinomycin supports that the influx is because of voltagegated channels in the E. coli cell membrane. These observations demonstrate diversity in photochemistry and mechanism among proteorhodopsins. Calculations of photon fluence rates at different ocean depths show that the difference in photocycle rates between GPR and BPR as well as their different absorption maxima may be explained as an adaptation to the different light intensities available in their respective marine environments. Finally, the results raise the possibility of regulatory (i.e. sensory) rather than energy harvesting functions of some members of the proteorhodopsin family.

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Section: Resultsmentioning

confidence: 77%

Spectroscopic and Photochemical Characterization of a Deep Ocean Proteorhodopsin

Wang

Sineshchekov

Spudich

et al. 2003

Journal of Biological Chemistry

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158

270

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“…From these data, it was suggested that the size of the amino acid might be involved in determining the color of the chromophore. Whether this assumption is connected to the hypsochromic shift and the fine structure of the absorption band of SR-Il and whether it can be reconciled with current models (15,33) (36,37), which are characterized by a deprotonated Schiff base. Whereas in SR-I only an environmental change of Asp-76 is observed (37), the photoactivation of pSR-II clearly leads to a protonation of a carboxylate group, most probably Asp-75 (36).…”

Section: A)(i W)agr(r D)ag(g S) the Parentheses Denote Po-mentioning

confidence: 95%

“…Although a partial purification was accomplished (12), information was mostly restricted to spectroscopic data and physiological properties (13,14). The absorption maximum occurs at 490 nm with a shoulder at 460 nm, suggesting a planar structure of the retinal chromophore (15). Its molecular mass of 24 kDa is typical for the bacterial rhodopsins.…”

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confidence: 99%

The primary structure of sensory rhodopsin II: a member of an additional retinal protein subgroup is coexpressed with its transducer, the halobacterial transducer of rhodopsin II.

Seidel

Scharf

Gautel

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

125

107

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The blue-light receptor genes (sopII) of sensory rhodopsin (SR) II were cloned from two species, the halophilic bacteria Haloarcula vallismortis (vSR-II) and Natronobacterium pharaonis (pSR-II). Upstream of both soplI gene loci, sequences corresponding to the halobacterial transducer of rhodopsin (Htr) II In bacterial taxis, the cell recognizes and reacts actively to numerous chemical and physical stimuli. A well-studied example is found in the chemotactic behavior ofEscherichia coli. The chemoreceptors of E. coli display two functional properties, the reception of the signal on the external side of the cell and the signal transduction to cytoplasmic proteins (reviewed in ref. 1). Characteristic of transducer proteins is their ability to adapt to a constant signal input by reversible methylation of specific sites flanking a cytoplasmic domain (signal domain), which links the incoming signal with cytoplasmic components.In a similar signal transduction system, the phototactic activity of the archaeon Halobacterium salinarium is mediated by photoreceptors (reviewed in refs. 2 and 3) that have a close structural relationship to the ion pumps of bacteriorhodopsin (BR) and halorhodopsin (reviewed in ref. 4). The bacteria are attracted to light >520 nm and repelled by light <500 nm. The photoattractant response of Halobacteria is mediated by sensory rhodopsin (SR) I. In a two-photon reaction, it can also trigger a negative response toward near-UV light. Moreover, repellent light of wavelengths <500 nm is recognized by a second pigment, SR-II, which absorbs at -490 nm.

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“…7A, dashed line). Both spectra lacked obvious vibrational fine structure, characteristic of the other relatively blue-shifted microbial rhodopsins CrChR2 (54,55) and haloarchaeal sensory rhodopsin II (56).…”

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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Color regulation in the archaebacterial phototaxis receptor phoborhodopsin (sensory rhodopsin II)

Cited by 114 publications

References 75 publications

Spectroscopic and Photochemical Characterization of a Deep Ocean Proteorhodopsin

Spectroscopic and Photochemical Characterization of a Deep Ocean Proteorhodopsin

The primary structure of sensory rhodopsin II: a member of an additional retinal protein subgroup is coexpressed with its transducer, the halobacterial transducer of rhodopsin II.

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

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