Properties of Synthetic Bacteriorhodopsin Pigments. Further Probes of the Chromophore Binding Site

Crouch, Rosalie K.; Scott, Rick; Ghent, Shawn; Govindjee, Rajni; Chang, Chung‐Ho; Ebrey, Thomas G.

doi:10.1111/j.1751-1097.1986.tb05608.x

Cited by 22 publications

(14 citation statements)

References 21 publications

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“…There are, however, no indications of deviation from the trend of longitudinal flexibility noted for the C-17 and the C-22 BR analogs. Among other examples of analogs with modified polyene chain length, particularly pertinent is a series of naphthalene-retinal analogs (Crouch et al, 1986). The latter results appear to be consistent with the ideas presented here.…”

supporting

confidence: 86%

BUTYL CONFORMATIONAL REORGANIZATION AS A POSSIBLE EXPLANATION FOR THE LONGITUDINAL FLEXIBILITY OF THE BINDING SITE OF BACTERIORHODOPSIN. THE AZULENE and C‐22 RETINOID ANALOGS*

Liu

et al. 1991

Photochem & Photobiology

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The UV-VIS absorption data of four bacteriorhodopsin (BR) analogs formed from azulene-retinals of varying polyene chain length show that the one-bond-shortened to one-bond-lengthened analogs possess comparable opsin shift values to that of BR. A two-bond-shortened analog exhibited a much smaller opsin shift. These data, combined with those reported for the C-22 retinal analog (Tokunaga et al., 1977, Biophys. J. 19, 191-198) were analyzed by molecular modelling and computer graphics in terms of a model where conformational flexibility of the appended butyl is the controlling factor in determining ease of pigment formation and protein/substrate interaction.

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supporting

confidence: 86%

BUTYL CONFORMATIONAL REORGANIZATION AS A POSSIBLE EXPLANATION FOR THE LONGITUDINAL FLEXIBILITY OF THE BINDING SITE OF BACTERIORHODOPSIN. THE AZULENE and C‐22 RETINOID ANALOGS*

Liu

et al. 1991

Photochem & Photobiology

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“…Literature on bR analog studies indeed reveals that the hydrophobic binding site of bR is not as restrictive as the visual pigment, e.g., capable of accepting chain-lengthened (i.e., ring-displaced) 10 and extensively ring-modifed analogs (naphthyl, 11 ringopened, 12 azulenic 13,14 ). A possible consequence of diminished protein inhibition is dynamic NMR behavior for these signals.…”

Section: Discussionmentioning

confidence: 96%

An F NMR Study of Bis(trifluoromethyl)phenyl Bacteriorhodopsin Analogs

et al. 1996

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Two bis-trifluoromethylated phenylretinal bacteriorhodopsin (bR) analogs were prepared and studied by F NMR and UV-vis spectroscopy. In contrast to those of visual pigments, only one fluorine signal was observed for the doubly labeled bR analogs. After considering different possible explanations, we believe the result probably reflects a more open hydrophobic pocket for the bR analogs allowing rapid equilibration (at the NMR scale) of the double labels. The extent of protein perturbation at the ortho position is different from that at the meta position.

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“…These studies have provided significant information on the steric and electronic properties of the chromophore binding site. The trimethyl cyclohexenyl ring of the native retinal (6) has been replaced by the phenyl (6)(7)(8), naphthyl (9)(10)(11)(12) and phenanthryl (13) rings (Fig. l), and it was concluded that the ring binding site is unrestrictive, at least to these systems.…”

Section: Introductionmentioning

confidence: 99%

Studies on Pyrylretinal Analogues of Bacteriorhodopsin

Das

Crouch²,

Govindjee³

et al. 1999

Photchem. Photbio.

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The retinal analogues 3-methyl-5-(1-pyryl)-2E,4E-pentadienal (1) and 3,7-dimethyl-9-(1-pyryl)-2E,4E,6E,8E-nonatetr aenal (2), which contain the tetra aromatic pyryl system, have been synthesized and characterized in order to examine the effect of the extended ring system on the binding capabilities and the function of bacteriorhodopsin (bR). The two bR mutants, E194Q and E204Q, known to have distinct proton-pumping patterns, were also examined so that the effect of the bulky ring system on the proton-pumping mechanism could be studied. Both retinals formed pigments with all three bacterioopsins, and these pigments were found to have absorption maxima in the range 498-516 nm. All the analogue pigments showed activity as proton pumps. The pigment formed from wild-type apoprotein bR with 1 (with the shortened polyene side chain) showed an M intermediate at 400 nm and exhibited fast proton release followed by proton uptake. Extending the polyene side chain to the length identical with retinal, analogue 2 with wild-type apoprotein gave a pigment that shows M and O intermediates at 435 nm and 650 nm, respectively. This pigment shows both fast and slow proton release at pH 7, suggesting that the pKa of the proton release group (in the M-state) is higher in this pigment compared to native bR. Hydrogen azide ions were found to accelerate the rise and decay of the O intermediate at neutral pH in pyryl 2 pigment. The pigments formed between 2 and E194Q and E204Q showed proton-pumping behavior similar to pigments formed with the native retinal, suggesting that the size of the chromophore ring does not alter the protein conformation at these sites.

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Properties of Synthetic Bacteriorhodopsin Pigments. Further Probes of the Chromophore Binding Site

Cited by 22 publications

References 21 publications

BUTYL CONFORMATIONAL REORGANIZATION AS A POSSIBLE EXPLANATION FOR THE LONGITUDINAL FLEXIBILITY OF THE BINDING SITE OF BACTERIORHODOPSIN. THE AZULENE and C‐22 RETINOID ANALOGS*

BUTYL CONFORMATIONAL REORGANIZATION AS A POSSIBLE EXPLANATION FOR THE LONGITUDINAL FLEXIBILITY OF THE BINDING SITE OF BACTERIORHODOPSIN. THE AZULENE and C‐22 RETINOID ANALOGS*

An F NMR Study of Bis(trifluoromethyl)phenyl Bacteriorhodopsin Analogs

Studies on Pyrylretinal Analogues of Bacteriorhodopsin

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