Cyanobacteriochromes: a new superfamily of tetrapyrrole-binding photoreceptors in cyanobacteria

Ikeuchi, Masahiko; Ishizuka, Takami

doi:10.1039/b802660m

Cited by 276 publications

(340 citation statements)

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“…Similarly, it has been suggested that two-Cys CBCRs can sense the cellular redox potential via oxidation of the second Cys, which arrests the photocycle (21). There also are many examples of tandem CBCR sensors containing multiple GAF domains that perceive light of various colors (1,2,14,19,23,24). CBCRs thus are exceptionally sophisticated photosensors, able to integrate light with various physiological cues and to provide complete coverage of the entire visible spectrum with a single chromophore precursor and a small, soluble protein sensor.…”

Section: Discussionmentioning

confidence: 99%

“…S1B). * Cyanobacteriochromes (CBCRs) are widespread cyanobacterial photosensors with phytochrome-related GAF domains (1,2,13,14). Although CBCRs also convert between two photostates via bilin photoisomerization at C15, they exhibit much more spectral diversity, with peak absorptions ranging from 330 to 680 nm and hence spanning the entire visible spectrum and near UV (13,(15)(16)(17)(18)(19)(20)(21)(22)(23)(24).…”

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confidence: 99%

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Green/red cyanobacteriochromes regulate complementary chromatic acclimation via a protochromic photocycle

Hirose

Rockwell

Nishiyama

et al. 2013

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

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Cyanobacteriochromes (CBCRs) are cyanobacterial members of the phytochrome superfamily of photosensors. Like phytochromes, CBCRs convert between two photostates by photoisomerization of a covalently bound linear tetrapyrrole (bilin) chromophore. Although phytochromes are red/far-red sensors, CBCRs exhibit diverse photocycles spanning the visible spectrum and the near-UV (330-680 nm). Two CBCR subfamilies detect near-UV to blue light (330-450 nm) via a "two-Cys photocycle" that couples bilin 15Z/15E photoisomerization with formation or elimination of a second bilincysteine adduct. On the other hand, mechanisms for tuning the absorption between the green and red regions of the spectrum have not been elucidated as of yet. CcaS and RcaE are members of a CBCR subfamily that regulates complementary chromatic acclimation, in which cyanobacteria optimize light-harvesting antennae in response to green or red ambient light. CcaS has been shown to undergo a green/red photocycle: reversible photoconversion between a green-absorbing 15Z state ( 15Z P g ) and a red-absorbing 15E state ( 15E P r ). We demonstrate that RcaE from Fremyella diplosiphon undergoes the same photocycle and exhibits light-regulated kinase activity. In both RcaE and CcaS, the bilin chromophore is deprotonated as 15Z P g but protonated as 15E P r . This change of bilin protonation state is modulated by three key residues that are conserved in green/red CBCRs. We therefore designate the photocycle of green/red CBCRs a "protochromic photocycle," in which the dramatic change from green to red absorption is not induced by initial bilin photoisomerization but by a subsequent change in bilin protonation state.light sensing | phycobiliprotein | signal transduction | spectral tuning | two-component signaling P hytochrome photosensors initially were discovered in plants and later found in cyanobacteria, nonoxygenic photosynthetic bacteria, nonphotosynthetic bacteria, fungi, and algae (1, 2). These photoreceptors bind linear tetrapyrrole (bilin) chromophores within a conserved GAF (cGMP phosphodiesterase/adenylyl cyclase/FhlA) domain via a covalent thioether linkage to a conserved Cys residue (Fig. S1A)(3-6). Upon illumination, phytochromes reversibly convert between a red-absorbing dark state and a far-red-absorbing photoproduct. This red/far-red photocycle is triggered by photoisomerization of the bilin 15,16-double bond between the 15Z and 15E configurations (7,8), with 15Z giving red absorption and 15E far-red absorption (4, 6, 9). In phytochromes, the conjugated π system of the bilin is protonated in both photostates, and this protonation is necessary to maintain the red and far-red absorption (10-12). Conserved GAF residues supply a hydrogen bond network to tune the chemical and spectral properties of the bilin (Fig. S1B).* Cyanobacteriochromes (CBCRs) are widespread cyanobacterial photosensors with phytochrome-related GAF domains (1,2,13,14). Although CBCRs also convert between two photostates via bilin photoisomerization at C15, they exhibit much more spe...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Green/red cyanobacteriochromes regulate complementary chromatic acclimation via a protochromic photocycle

Hirose

Rockwell

Nishiyama

et al. 2013

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

Self Cite

153

265

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“…They are related to the red/far red responsive canonical phytochromes (Phys), 2 but absorb light at different wavelengths; the absorptions of the different CBCRs nearly cover the entire visible spectrum. 1,3,4 In contrast to canonical Phys, the sensory modules of CBCRs consist of several GAF domains (GAF, acronym of cGMP phosphodiesterase, adenylyl cyclase and FhlA protein domain), of which one or more bind covalently open-chain tetrapyrroles as photoactive chromophores.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7][8][9] There are several advantages of Phys 10 and CBCRs, 1 or domains thereof, that make them potentially interesting tools in biological analytics: they can be obtained by heterologous co-expression of protein-and chromophorecoding genes; and chromophore attachment is autocatalytic and does not require co-expression of lyases. 11 Their use as fluorescent biomarkers is impaired, however, by the relatively low fluorescence quantum yield.…”

Section: Introductionmentioning

confidence: 99%

Orange fluorescent proteins constructed from cyanobacteriochromes chromophorylated with phycoerythrobilin

Sun

Tang

et al. 2014

Photochem Photobiol Sci

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Cyanobacteriochromes are a structurally and spectrally highly diverse class of phytochrome-related photosensory biliproteins. They contain one or more GAF domains that bind phycocyanobilin (PCB) autocatalytically; some of these proteins are also capable of further modifying PCB to phycoviolobilin or rubins. We tested the chromophorylation with the non-photochromic phycoerythrobilin (PEB) of 16 cyanobacteriochrome GAFs from Nostoc sp. PCC 7120, of Slr1393 from Synechocystis sp. PCC 6803, and of Tlr0911 from Thermosynechococcus elongatus BP-1. Nine GAFs could be autocatalytically chromophorylated in vivo/in E. coli with PEB, resulting in highly fluorescent biliproteins with brightness comparable to that of fluorescent proteins like GFP. In several GAFs, PEB was concomitantly converted to phycourobilin (PUB) during binding. This not only shifted the spectra, but also increased the Stokes shift.The chromophorylated GAFs could be oligomerized further by attaching a GCN4 leucine zipper domain, thereby enhancing the absorbance and fluorescence of the complexes. The presence of both PEB and PUB makes these oligomeric GAF-"bundles" interesting models for energy transfer akin to the antenna complexes found in cyanobacterial phycobilisomes. The thermal and photochemical stability and their strong brightness make these constructs promising orange fluorescent biomarkers.

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“…We like to think that as humans we have a highly developed sense of colour vision, but even these cyanobacteria are able to detect light of different wavelengths. 30,31 Why should these primitive organisms need such a complex system of chromatic detection? Cyanobacteria live in water columns, which at the surface are illuminated by light of a wide variety of wavelengths but where at depth blue light predominates.…”

Section: Evolution Of Visionmentioning

confidence: 99%

Light and the evolution of vision

Williams

2015

Eye

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It might seem a little ridiculous to cover the period over which vision evolved, perhaps 1.5 billion years, in only 3000 words. Yet, if we examine the photoreceptor molecules of the most basic eukaryote protists and even before that, in those of prokaryote bacteria and cyanobacteria, we see how similar they are to those of mammalian rod and cone photoreceptor opsins and the photoreceptive molecules of light sensitive ganglion cells. This shows us much with regard the development of vision once these proteins existed, but there is much more to discover about the evolution of even more primitive vision systems.

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Cyanobacteriochromes: a new superfamily of tetrapyrrole-binding photoreceptors in cyanobacteria

Cited by 276 publications

References 65 publications

Green/red cyanobacteriochromes regulate complementary chromatic acclimation via a protochromic photocycle

Green/red cyanobacteriochromes regulate complementary chromatic acclimation via a protochromic photocycle

Orange fluorescent proteins constructed from cyanobacteriochromes chromophorylated with phycoerythrobilin

Light and the evolution of vision

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