Abstract
The intermediates of trans-bacteriorhodopsin (trans-bR) in the photoreaction cycle were investigated under two different conditions. In a low salt and neutral pH medium (10 mM phosphate buffer, pH 6.6), trans-bR was irradiated with 500 nm light at −190‡ C, resulting in formation of batho-trans-bR (batho-bRt). On warming in the dark, batho-bRt converted to lumi-trans-bR (lumi-bRt), meta-trans-bR (meta-bRt) and finally to trans-bR. The intermediates N and O, which had been detected by others by flash photolysis, were not observed. The thermal decay of lumi-bRt in a high salt and high pH medium (10 mM borate buffer with l M NaCl, pH 10.0) proceeded simultaneously through two pathways; one to meta-bRt and another to trans-bR. About 72% of lumi-bRt converted to trans-bR directly and the residue converted to meta-bRt. By use of this value, the absorption spectra of batho-bRt (λmax: 626 nm), lumi-bRt (λmax: 543 nm) and meta-bRt (λmax: 418 nm) were calculated. A photoreaction cycle of bacteriorhodopsin was proposed on the basis of the above findings.
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Becher B, Ebrey T (1977) The quantum efficiency for the photochemical conversion of the purple membrane protein. Biophys J 17: 185–191
Becher B, Tokunaga F, Ebrey TG (1978) Ultraviolet and visible absorption spectra of the purple membrane protein and the photocycle intermediates. Biochemistry 17: 2293–2300
Blaurock AE, Stoeckenius W (1971) Structure of the purple membrane. Nature [New Biol] 233: 152–155
Chu Kung M, Devault D, Hess B, Oesterhelt D (1975) Photolysis of bacterial rhodopsin. Biophys J 15: 907–911
Cone RA (1972) Rotational diffusion of rhodopsin in the visual receptor membrane. Nature [New Biol] 236: 39–43
Danon A, Stoeckenius W (1974) Photophosphorylation in Halobacterium halobium. Proc Natl Acad Sci USA 70: 2853–2857
Dencher N, Wilms M (1975) Flash photometric experiments on the photochemical cycle of bacteriorhodopsin. Biophys Struct Mech 1: 259–271
Fisher E (1967) The calculation of photostationary states in system A ⇄ B when only A is known. J Phys Chem 71: 3704–3706
Hurley JB, Ebrey TG (1978) Energy transfer in the purple membrane of Halobacterium halobium. Biophys J 22: 49–66
Korenstein R, Hess B, Kushimitz D (1978) Branching reactions in photocycle of bacteriorhodopsin. FEBS Lett 93: 266–270
Lanyi JK, Renthal R, MacDonald RE (1976) Light induced glutamate transport in Halobacterium halobium envelope vesicles. II: Evidence that the driving force is a light-dependent sodium gradient. Biochemistry 15: 1603–1609
Lozier RH, Bogomolni RA, Stoeckenius W (1975) Bacteriorhodopsin: A light-driven proton pump in Halobacterium halobium. Biophys J 15: 955–962
Lozier RH, Niederberger W (1977) The photochemical cycle of bacteriorhodopsin. Fed Proc 36: 1805–1809
Maeda A, Iwasa T, Yoshizawa T (1977) Isomeric composition of retinal chromophore in dark-adapted bacteriorhodopsin. J Biochem (Tokyo) 82: 1599–1604
Michel H, Oesterhelt D (1976) Light induced change of the pH-gradient and the membrane potential in Halobacterium halobium. FEBS Lett 65: 175–178
Oesterhelt D, Hess B (1973) Reversible photolysis of the purple complex in the purple membrane of Halobacterium halobium. Eur J Biochem 37: 316–326
Oesterhelt D, Stoeckenius W (1971) Rhodopsin-like protein from the purple membrane of Halobacterium halobium. Nature [New Biol] 233: 149–152
Oesterhelt D, Stoeckenius W (1973) Functions of a new photoreceptor membrane. Proc Natl Acad Sci USA 70: 2853–2857
Oesterhelt D, Stoeckenius W (1974) Isolation of the cell membrane of Halobacterium halobium and its fractionation into red and purple membrane. In: Fleisher S, Packer L (eds) Methods in enzymology, Vol 31: Biomembranes Part A. Academic Press, New York, pp 667–678
Pettei MJ, Yudd AP, Nakanishi K, Henselman R, Stoeckenius W (1977) Identification of retinal isomers isolated from bacteriorhodopsin. Biochemistry 16: 1955–1959
Racker E, Stoeckenius W (1974) Reconstitution of purple membrane vesicles catalyzing light-driven proton up-take and adenosine triphosphate formation. J Biol Chem 249: 662–663
Sherman WV, Korenstein R, Caplan SR (1976a) Energetics and chronology of phototransients in the light response of the purple membrane of Halobacterium halobium. Biochim Biophys Acta 430: 454–458
Sherman WV, Silfkin NA, Caplan SR (1976b) Kinetic studies of phototransients in bacteriorhodopsin. Biochim Biophys Acta 423: 238–248
Tokunaga F, Iwasa T, Yoshizawa T (1976) Photochemical reaction of bacteriorhodopsin. FEBS Lett 72: 33–38
Yoshizawa T (1972) The behaviour of visual pigments at low temperatures. In: Dartnall HJA (ed) Handbook of sensory physiology, Vol VII/1: Photochemistry of vision. Springer, Berlin Heidelberg New York, pp 146–179
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Iwasa, T., Tokunaga, F. & Yoshizawa, T. A new pathway in the photoreaction cycle of trans-bacteriorhodopsin and the absorption spectra of its intermediates. Biophys. Struct. Mechanism 6, 253–270 (1980). https://doi.org/10.1007/BF00538227
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DOI: https://doi.org/10.1007/BF00538227