Protonation of a novel intermediate P is involved in the M → bR step of the bacteriorhodopsin photocycle

Drachev, Lel A.; Kaulen, Andrey D.; Скулачев, В.П.; Zorina, V.V.

doi:10.1016/0014-5793(86)81134-6

Cited by 57 publications

(51 citation statements)

References 2 publications

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“…This figure indicates that the amount of N decreases with increasing actinic light density. This is in accordance with the results of Drachev and co-workers [13], and Fig. 5a is a more convincing evidence for this, than obtained from where exponential components were fitted to similar absorption kinetic data.…”

Section: The Kinetics Of the N Intermediatesupporting

confidence: 93%

Cooperativity‐regulated parallel pathways of the bacteriorhodopsin photocycle

Tokaji

1995

FEBS Letters

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Section: The Kinetics Of the N Intermediatesupporting

confidence: 93%

Cooperativity‐regulated parallel pathways of the bacteriorhodopsin photocycle

Tokaji

1995

FEBS Letters

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“…Others have stressed that such multiexponential processes can arise from a single species in equilibrium with other intermediates (8). El-Sayed and coworkers (9) Finally, we propose that R, the very slowly decaying photocycle intermediate (10)(11)(12), may be in a different photocycle than either of those containing the M forms.…”

mentioning

confidence: 63%

“…We assign this difference spectrum to the R intermediate because of its long decay time and its striking similarity with the R spectrum reported earlier (11). Because of the likelihood that the absorption maximum of R is close to that of its parent pigment (11,12), the difference spectrum does not provide a good estimate for the maximum of either the parent pigment or the R intermediate.…”

Section: N4mentioning

confidence: 99%

Independent photocycles of the spectrally distinct forms of bacteriorhodopsin

Dancsházy

Govindjee

Ebrey

1988

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

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Time-resolved, flash-induced difference absorbance spectra (300-700 am) at pH 10.5 and 5C for the bacteriorhodopsin photocycle fast and slow decaying forms of the M intermediate (M' and MS, respectively) MATERIALS AND METHODS Purple membranes were isolated from Halobacterium halobium, S9 strain, and suspended in 30 mM piperazine/30 mM glycylglycine, pH 10.5. All samples contained 40%o (vol/vol) glycerol except those used for the flash-induced absorbance changes in Fig. 4. All measurements were carried out on light-adapted BR.Two spectrophotometers were used to obtain the lightinduced difference spectra. For the faster measurements, the data were taken and analyzed as described (10,11). For the slower measurements a Hewlett-Packard model 8452A diode array spectrophotometer was used to take complete lightinduced difference spectra from 300 to 700 nm with 2-nm spectral resolution. (The absorption spectrum of the lightadapted sample was used as the baseline.) The actinic source was a commercial photoflash with Coming long-pass filter (CS 3-67, wavelength >550 nm). The half-duration time was 150 tUs. Since the measuring beam of the diode array spectrophotometer was relatively strong white light, special care was taken to check and avoid a possible actinic effect of the measuring beam. Sample OD570 was between 1.3 and 1.5. RESULTSSeparation of the Difference Spectra of Intermediates M', ME, and R. From the time-dependent series of difference spectra, we can determine the difference spectra of the late intermediates involved in the BR recovery at high pH (Mf, MS, and R). We have chosen conditions for which the differences in the lifetimes and yields of these three components are maximal. We assume that the intermediates before M can be neglected because of their much shorter lifetimes and that no significant amount of the late intermediate 0 is formed because of the low temperatures and high pH values (refs. 5, 6, and 10 and unpublished data). Fig. 1 6358The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

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“…Drachev et al [2] found light-induced absorbance changes which occur more slowly than the disappearance of the M intermediate but synchronous with proton uptake in a suspension of purple membranes. Based on this finding they proposed a new intermediate, P, which follows M and is coupled to proton uptake by bR.…”

Section: Introductionmentioning

confidence: 98%

“…3. Absorption spectra of intermediate N (1) and its bathoform KS (2) in water suspension of purple membrane frozen to -196°C.…”

Section: Introductionmentioning

confidence: 99%