Structural changes in bacteriorhodopsin induced by electric impulses

Tsuji, Kinko; Neumann, Eberhard

doi:10.1016/0141-8130(81)90033-7

Cited by 35 publications

(20 citation statements)

References 28 publications

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“…4) were calculated using Eqs. (8) and (10) with the corresponding coefficients well correlating with the experimental data obtained for the oriented PM films under neutral and acidic conditions (see Fig. 1(b)).…”

Section: Discussionsupporting

confidence: 61%

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Estimation of the permanent dipole moment of bacteriorhodopsin

Kietis¹

2010

Lithuanian J. Phys.

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The static electric dipole moment persisting in bacteriorhodopsin was defined from electro-acoustic measurements of the dried films of purple membranes and compared with the value estimated from quantum chemical calculations. The projection of this value normal to the membrane surface is experimentally estimated to be equal to 40 D and oriented from the cytoplasmic side to the extracellular side of the membrane. This value is almost independent of the environment pH. QM/MM calculations were also performed for the known structures of the ground and intermediate states of bacteriorhodopsin. According to calculations the dipole moment is mainly determined by the cytoplasmic and extracellular coils, while the contribution from the transmembrane helices is smaller and of the opposite direction, and this value corresponding to the active centre is small. The calculated values of the dipole moment of bacteriorhodopsin in the intermediate states K, L, and M provide understanding about the origin of the driving force for the proton pumping. Employing the values of the dipole moments corresponding to the ground and intermediate states of bacteriorhodopsin, defined by means of QM/MM calculations, the experimentally determined photoelectric response of the dried films is explained.

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Section: Discussionsupporting

confidence: 61%

“…Membrane proteins are asymmetric in most cases due to the presence of surface electric charges and dipoles [4][5][6][7][8][9]. Possibilities of orientation of the PM evidently confirm the existence of a permanent dipole moment at low frequencies and an induced dipole moment at high frequencies of the applied field [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 94%

Estimation of the permanent dipole moment of bacteriorhodopsin

Kietis¹

2010

Lithuanian J. Phys.

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“…Such data were obtained for purple membranes and apomem branes after the application of an electric field with E = 2 ⋅ 10 5 -3 ⋅ 10 6 V/m 2 [55][56][57][58]. Optoelectric mea surements in a suspension of the purple membranes demonstrated that a strong electric field resulted in a change in the BR optical properties at the wavelength of the chromophore absorption (λ = 565 nm) and in the area of 400 nm.…”

Section: Electro Activation and Photo Activation Of Opsinmentioning

confidence: 85%

“…Optoelectric mea surements in a suspension of the purple membranes demonstrated that a strong electric field resulted in a change in the BR optical properties at the wavelength of the chromophore absorption (λ = 565 nm) and in the area of 400 nm. The contribution of the compo nent that absorbed at 400 nm was sometimes higher than that at 565 nm [55]. Therefore, two components that are sensitive to the electric field were identified in BR: retinal and labile charged and polar compo nents of the protein structure.…”

Section: Electro Activation and Photo Activation Of Opsinmentioning

confidence: 99%

“…Therefore, two components that are sensitive to the electric field were identified in BR: retinal and labile charged and polar compo nents of the protein structure. It was especially important that the external electric field affected the electrooptic properties of retinal both directly and through a local rearrangement of the opsin groups in the retinal environment due to induced electric charges in the positions of different charged, polar, and polarized groups [55]. Thus, the highly polar properties of both retinal and the protein globule itself play a determining role in the BR interaction with an electric field.…”

Section: Electro Activation and Photo Activation Of Opsinmentioning

confidence: 99%

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Photo-induced processes and the reaction dynamics of bacteriorhodopsin

Terpugov

Degtyareva

2015

BIOPHYSICS

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In recent years, a large body of data on the structure and dynamic properties of bacteriorhodopsin has been obtained at the atomic level with high temporal and spatial resolution. This information has been summarized in many reviews. In this review, we focused on the recent advances in observing the photo induced response of bacteriorhodopsin and understanding the mechanisms of retinal-protein interactions, which are still unclear. We discuss our recent spectroscopic data that was obtained for the wild type bacteriorhodopsin and model amino acid compounds using FT IR emission spectroscopy and UV spectroscopy in the visible area. We attempt to find an answer to one of the most important questions concerning the role of protein in bacteriorhodopsin in the primary processes on the basis of the characteristics of the structure and optical prop erties of glycine and L lysine, which model the photo induced behavior of opsin under natural conditions.

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Electric birefringence study of the purple membrane of Halobacterium halobium

Kahn

1984

Biopolymers

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SynopsisAn electric birefringence study was carried out on aqueous suspensions of the purple membrane of Halobacterium halobium. In addition to the characterization of both native and modified membrane samples, the dependence of electric birefringence on p H and ionic strength was also investigated. The results indicate that purple membrane shows electric birefringence a t a field strength a s low as 200 V/cm. T h e permanent dipole moment and polarizability ranged from 20,500 debyes and 1.01 X cm3 for a purple membrane concentration of 0.40 mg/mI, to 41,000 debyes and 2.05 X cm:' for a concentration of 0.80 mg/mL. It was also found that removal of the retinyl group of bacteriorhodopsin substantially decreases but does not eliminate the electric birefringence of the membrane. The solubilization of the membrane by Triton X-100, however, completely abolishes the electric birefringence. These experiments indicate that there is an interaction between adjacent bacteriorhodopsin molecules within the purple membrane via the retinyl chromophore moiety that builds u p the permanent dipole moment. They also suggest that there are two types of response when purple membrane suspensions are placed in an electric field. One is an alignment of the disk-shaped particles with the field. Theother is a stacking of the particles following their alignment by the electric field, which is promoted by the induced dipole moment.

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Structural changes in bacteriorhodopsin induced by electric impulses

Cited by 35 publications

References 28 publications

Estimation of the permanent dipole moment of bacteriorhodopsin

Estimation of the permanent dipole moment of bacteriorhodopsin

Photo-induced processes and the reaction dynamics of bacteriorhodopsin

Electric birefringence study of the purple membrane of Halobacterium halobium

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