Effect of salt on photocycle and ion-pumping of halorhodopsin and third rhodopsinlike pigment of Halobacterium halobium

Hazemoto, Norio; Kamo, Naoki; Kobatake, Yonosuke; Tsuda, Motoyuki; Terayama, Yoshio

doi:10.1016/s0006-3495(84)84254-x

Cited by 46 publications

(15 citation statements)

References 16 publications

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“…Upon light excitation, chloride ions are transferred from the medium into the cell (35,65,496,534). The ion selectivity of the transport is not restricted to chloride; bromide, iodide, and nitrate are also transported (203,208,496). Compared to that of BR, the absorption maximum of HR has a longer wavelength.…”

Section: Hrmentioning

confidence: 99%

Bioenergetics of the Archaea

Schäfer

Engelhard

Müller³

1999

Microbiol Mol Biol Rev

265

147

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SUMMARY In the late 1970s, on the basis of rRNA phylogeny, Archaea (archaebacteria) was identified as a distinct domain of life besides Bacteria (eubacteria) and Eucarya. Though forming a separate domain, archaea display an enormous diversity of lifestyles and metabolic capabilities. Many archaeal species are adapted to extreme environments with respect to salinity, temperatures around the boiling point of water, and/or extremely alkaline or acidic pH. This has posed the challenge of studying the molecular and mechanistic bases on which these organisms can cope with such adverse conditions. This review considers our cumulative knowledge on archaeal mechanisms of primary energy conservation, in relationship to those of bacteria and eucarya. Although the universal principle of chemiosmotic energy conservation also holds for Archaea, distinct features have been discovered with respect to novel ion-transducing, membrane-residing protein complexes and the use of novel cofactors in bioenergetics of methanogenesis. From aerobically respiring archaea, unusual electron-transporting supercomplexes could be isolated and functionally resolved, and a proposal on the organization of archaeal electron transport chains has been presented. The unique functions of archaeal rhodopsins as sensory systems and as proton or chloride pumps have been elucidated on the basis of recent structural information on the atomic scale. Whereas components of methanogenesis and of phototrophic energy transduction in halobacteria appear to be unique to archaea, respiratory complexes and the ATP synthase exhibit some chimeric features with respect to their evolutionary origin. Nevertheless, archaeal ATP synthases are to be considered distinct members of this family of secondary energy transducers. A major challenge to future investigations is the development of archaeal genetic transformation systems, in order to gain access to the regulation of bioenergetic systems and to overproducers of archaeal membrane proteins as a prerequisite for their crystallization.

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Section: Hrmentioning

confidence: 99%

Bioenergetics of the Archaea

Schäfer

Engelhard

Müller³

1999

Microbiol Mol Biol Rev

265

147

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“…Flash photolysis of halorhodopsin Intermediates of the photocycle of HR have been described (Weber and Bogomolni, 1981;Tsuda et al, 1982;Schobert et al, 1983;Steiner et al, 1984;Hazemoto et al, 1984). When a ratio of -1:1 was reached, the yellow light was turned off and the initial velocity of HR578 formation was measured as a function of blue light intensity.…”

Section: Introductionmentioning

confidence: 99%

The photocycle of the chloride pump halorhodopsin. II: Quantum yields and a kinetic model

1985

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The quantum yield of the primary photoreaction of HR578 was determined as øgreen = 0.34±0.02 and that of the photochemical reconversion of HRL410 into HR578 as øblue = 0.01±0.004. From steady‐state illumination and flash‐photolysis experiments, a quantitative description of HRL410 formation and decay was made leading to a model of the photocycle in isolated, light‐adapted HR. This model satisfies all known facts about HR including its photochromic behaviour.

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“…sR was found in bR-and hRmutant strains selected by an excellent method (9), while sR's characteristic slow photocyle kinetics were reported independently (10). The spectrophotometric character of sR is described elsewhere (11)(12)(13)). The mutant strains showed both positive and negative phototaxis (8) (in this report, we use the conventional term positive and negative phototaxis for the photobehavioral responses of the cells to attractant and repellent light).…”

Section: Introductionmentioning

confidence: 99%

Negative Phototaxis from Blue Light and the Role of Third Rhodopsinlike Pigment in Halobacterium Cutirubrum

Takahashi¹,

Watanabe²,

Kamo³

et al. 1985

Biophysical Journal

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Wild-type cells of Halobacterium cutirubrum show phototaxis. In negative phototaxis the cells are repelled by blue-near ultraviolet light, and in positive phototaxis the cells are attracted to green-red light. The extent of the responses are measured by monitoring the changes in the reversal frequency of the swimming direction of cells using a computer-linked automated method as described previously (Takahashi, T., and Y. Kobatake, 1982, Cell. Struct. Funct., 7:183-192). When the intensity of the background light (illumination for the observation) was dramatically reduced, the sensitivity of the cells to the repellent light decreased markedly. This result has been previously explained by Bogomolni and Spudich (1982, Proc. Natl. Acad. Sci. USA, 79:6250-6254), who proposed that the photoreceptor for negative phototaxis is the long-lifetime intermediate in the photocycle of slow-rhodospin. The behavioral response in the negative phototaxis is dependent upon the intensity of the actinic light and the background light. This agrees quantitatively with our model based on the aforementioned hypothesis.

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Effect of salt on photocycle and ion-pumping of halorhodopsin and third rhodopsinlike pigment of Halobacterium halobium

Cited by 46 publications

References 16 publications

Bioenergetics of the Archaea

Bioenergetics of the Archaea

The photocycle of the chloride pump halorhodopsin. II: Quantum yields and a kinetic model

Negative Phototaxis from Blue Light and the Role of Third Rhodopsinlike Pigment in Halobacterium Cutirubrum

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