Rhodopsin(s) in eubacteria

Hoff, Wouter D.; Matthijs, H.C.P.; Schubert, Hendrik; Hellingwerf, Klaas J.

doi:10.1016/0301-4622(95)00033-t

Cited by 23 publications

(13 citation statements)

References 22 publications

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“…It has been suggested that a rhodopsin might act as a green light photoreceptor in Calothrix (Hoff et al ., 1995), and spectrophotometric analysis of an orange spot at the tip of the apical cell of the filamentous cyanobacterium Leptolyngbya also led the authors to suggest the presence of a rhodopsin‐like protein (Albertano et al ., 2000).…”

Section: Discussionmentioning

confidence: 99%

Demonstration of a sensory rhodopsin in eubacteria

Jung

Trivedi

Spudich

2003

Molecular Microbiology

235

295

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SummaryWe report the first sensory rhodopsin observed in the eubacterial domain, a green light-activated photoreceptor in Anabaena ( Nostoc ) sp. PCC7120, a freshwater cyanobacterium. The gene encoding the membrane opsin protein of 261 residues (26 kDa) and a smaller gene encoding a soluble protein of 125 residues (14 kDa) are under the same promoter in a single operon. The opsin expressed heterologously in Escherichia coli membranes bound all-trans retinal to form a pink pigment ( l l l l max 543 nm) with a photochemical reaction cycle of 110 ms half-life (pH 6.8, 18 ∞ ∞ ∞ ∞ C). Co-expression with the 14 kDa protein increased the rate of the photocycle, indicating physical interaction with the membrane-embedded rhodopsin, which we confirmed in vitro by affinity enrichment chromatography and Biacore interaction. The pigment lacks the proton donor carboxylate residue in helix C conserved in known retinylidene proton pumps and did not exhibit detectable proton ejection activity. We detected retinal binding to the protein in Anabaena membranes by SDS-PAGE and autofluorography of 3 H-labelled all-trans retinal of reduced membranes from the organism. We conclude that Anabaena rhodopsin functions as a photosensory receptor in its natural environment, and suggest that the soluble 14 kDa protein transduces a signal from the receptor. Therefore, unlike the archaeal sensory rhodopsins, which transmit signals by transmembrane helix-helix interactions with membraneembedded transducers, the Anabaena sensory rhodopsin may signal through a soluble cytoplasmic protein, analogous to higher animal visual pigments.

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Section: Discussionmentioning

confidence: 99%

Demonstration of a sensory rhodopsin in eubacteria

Jung

Trivedi

Spudich

2003

Molecular Microbiology

235

295

View full text Add to dashboard Cite

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“…Our preliminary data indicate that this Nostoc enzyme also catalyses the synthesis of retinal from apocarotenals. Further evidence on the occurrence of retinal in cyanobacteria has been reported from Calothrix, where a rhodopsin was supposed to act as a green-light photoreceptor (Hoff et al, 1995). However, the genome of Synechocystis does not encode a polypeptide with significant homology to any known opsin.…”

Section: Discussionmentioning

confidence: 99%

Retinal biosynthesis in Eubacteria: in vitro characterization of a novel carotenoid oxygenase from Synechocystis sp. PCC 6803

Ruch

Beyer

Ernst³

et al. 2005

Molecular Microbiology

113

131

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“…Many membrane proteins of different function and origin like bacteriorhodopsin (38), cytochrome oxidase (39), and the glycophorin A receptor (40) have been reported to occur either as trimers (PS I and bacteriorhodopsin) or as dimers (all other cases). The reason for this oligomerization is unknown.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Oligomerization of a Membrane Protein Complex

Kruip

Karapetyan

Терехова

et al. 1999

Journal of Biological Chemistry

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Many membrane proteins can be isolated in different oligomeric forms. Photosystem I (PSI), for example, exists in cyanobacteria either as a monomeric or as a trimeric complex. Neither the factors responsible for the specific trimerization process nor its biological role are known at present. In the filamentous cyanobacterium Spirulina platensis, trimers in contrast to monomers show chlorophyll fluorescence emission at 760 nm. To investigate the oligomerization process as well as the nature of the long wavelength chlorophylls, we describe here an in vitro reconstitution procedure to assemble trimeric PS I from isolated purified PS I monomers. Monomers (and trimers) were extracted from S. platensis with n-dodecyl ␤-D-maltoside and further purified by perfusion chromatography steps. The isolated complexes had the same polypeptide composition as other cyanobacteria (PsaA-PsaF and PsaI-PsaM), as determined from high resolution gels and immunoblotting. They were incorporated into proteoliposomes, which had been prepared by the detergent absorption method, starting from a phosphatidylcholine:phosphatidic acid mixture solubilized by octylglucoside. After the addition of monomeric PS I (lipid:chlorophyll, 25:1), octylglucoside was gradually removed by the stepwise addition of Biobeads. The 77 K fluorescence emission spectrum of these proteoliposomes displays a long wavelength emission at 760 nm that is characteristic of PS I trimers, which indicates for the first time the successful in vitro reconstitution of PS I trimers. In addition, a high performance liquid chromatography analysis of complexes extracted from these proteoliposomes confirms the formation of structural trimers. We also could show with this system 1) that at least one of the stromal subunits PsaC, -D, and -E is necessary for trimer formation and 2) that the extreme long wavelength emitting chlorophyll is formed as a result of trimer formation.

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Rhodopsin(s) in eubacteria

Cited by 23 publications

References 22 publications

Demonstration of a sensory rhodopsin in eubacteria

Demonstration of a sensory rhodopsin in eubacteria

Retinal biosynthesis in Eubacteria: in vitro characterization of a novel carotenoid oxygenase from Synechocystis sp. PCC 6803

In Vitro Oligomerization of a Membrane Protein Complex

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