The interaction of Triton X-100 with purple membrane

González-Mañas, Juan Manuel; Montoya, Guillermo; Rodríguez-Fernández, C; Gurtubay, J. I. G.; Goñi, Félix M.

doi:10.1016/0005-2728(90)90139-u

Cited by 10 publications

(11 citation statements)

References 19 publications

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“…However, this blue shift cannot be solely due to the isomer composition change in these two states, because for example, the dark-adapted state of bR trimer has its max shifted to 560 nm when the (all-trans) decreases to 45%. In addition, the DA-monomer has its max further shift to 546 nm in which (all-trans)/(13-cis) becomes 40/60 (Gonzalez-Manas et al, 1990), similar to that in the DA-trimer. There-fore, the most important reason for the blue shift of retinal absorption in the monomer is the environmental changes of the retinal binding site, as has been seen in many other cases, e.g., the mutation of the Schiff base proton acceptor Asp-85 to a neutral group shifts the retinal absorption maximum to 604 nm (Song et al, 1993).…”

Section: Resultsmentioning

confidence: 86%

“…The retinal isomer compositions and absorption maxima ( max ) have been listed in Table 1. It has been determined (Gonzalez-Manas et al, 1990) that the concentration of all-trans decreases from 94% to as low as 84% as bR becomes monomerized (0.01 M Triton X-100) under the LA condition. However, this blue shift cannot be solely due to the isomer composition change in these two states, because for example, the dark-adapted state of bR trimer has its max shifted to 560 nm when the (all-trans) decreases to 45%.…”

Section: Resultsmentioning

confidence: 99%

“…† Isomer ratio data are taken from a previous result at pH 6 (Song et al, 1995). ‡ Isomer ratio data are taken from a previous result at 20 mM Tris buffer, pH 5 (Gonzalez-Manas et al, 1990). Experimental conditions: 25 mM K 2 HPO 4 buffer, pH ϳ7.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, the monomeric bR is less thermally stable than its native trimeric form (Brouillette et al, 1989). In the dark-adapted (DA) state of bR monomer, the isomeric ratio of (all-trans)/(13cis) is determined to be 40/60 (Gonzalez-Manas et al, 1990), whereas in bR trimer it is close to 50/50, whereas in the LA state, this ratio is 95/5 for bR trimer (Song et al, 1995) and it varies from 65/35 to 85/15 for bR monomer (Gonzalez-Manas et al, 1990). These observations suggest that protein-protein, protein-lipids, and protein-retinal interactions influence the retinal configuration and the relative stability of its isomeric forms.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the Dynamics of the Primary Events of Bacteriorhodopsin in Its Trimeric and Monomeric States

Wang¹,

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Heyes

et al. 2002

Biophysical Journal

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In this paper, femtosecond pump-probe spectroscopy in the visible region of the spectrum has been used to examine the ultrafast dynamics of the retinal excited state in both the native trimeric state and the monomeric state of bacteriorhodopsin (bR). It is found that the excited state lifetime (probed at 490 nm) increases only slightly upon the monomerization of bR. No significant kinetic difference is observed in the recovery process of the bR ground state probed at 570 nm nor in the fluorescent state observed at 850 nm. However, an increase in the relative amplitude of the slow component of bR excited state decay is observed in the monomer, which is due to the increase in the concentration of the 13-cis retinal isomer in the ground state of the light-adapted bR monomer. Our data indicate that when the protein packing around the retinal is changed upon bR monomerization, there is only a subtle change in the retinal potential surface, which is dependent on the charge distribution and the dipoles within the retinal-binding cavity. In addition, our results show that 40% of the excited state bR molecules return to the ground state on three different time scales: one-half-picosecond component during the relaxation of the excited state and the formation of the J intermediate, a 3-ps component as the J changes to the K intermediate where retinal photoisomerization occurs, and a subnanosecond component during the photocycle.

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of the Dynamics of the Primary Events of Bacteriorhodopsin in Its Trimeric and Monomeric States

Wang¹,

Link

Heyes

et al. 2002

Biophysical Journal

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show abstract

“…53 Additionally, the well-known effect of the blue shift of the absorption maxima of the dark and lightadapted states of BR upon solubilization is evidence for conformational changes occurring at the level of the retinal-binding pocket. 50,55,56 Furthermore, significant conformational changes were detected for detergent-solubilized BR by NMR studies, 53 pointing to an effect on both transmembrane helices and connecting loops, thereby influencing the functional properties of the protein. Another example is the Ca 2C -ATPase from sarcoplasmic reticulum, for which it has been shown that different detergents and, especially, different contents of native lipids in sample preparations strongly influence the oligomerization state of the protein, thereby altering its activity.…”

Section: Discussionmentioning

confidence: 99%