Assignment of the anomalous resonance Raman vibrations of bathorhodopsin

Eyring, Gregory; Curry, Bostick; Mathies, Richard A.; Broek, Albert; Lugtenburg, J.

doi:10.1021/ja00536a046

Cited by 41 publications

(18 citation statements)

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“…It is now known from extensive isotopic substitution studies on bathorhodopsin, the primary photoproduct in vision, that Raman lines in this spectral region are due to the HOOP vibrations of the retinyl chain vinyl protons (15)(16)(17). The HOOP assignment for the 811-and 957-cm-' lines in K has been confirmed by spectra of K containing retinals deuterated at the 10, 11, 12 and 14 positions (unpublished data).…”

Section: Resultsmentioning

confidence: 78%

“…However, in bathorhodopsin, several HOOP modes appear with intensity comparable to that ofthe ethylenic stretching vibration (13)(14)(15)(16)(17). This strong enhancement of HOOP modes is not sensitive to the choice of excitation wavelength because these modes are observed as strong lines in bathorhodopsin spectra obtained with excitation ranging from 476 to 585 nm (13)(14)(15)(16)(17). Calculations have shown that enhanced HOOP Raman intensities are likely to be caused by torsional deformations of the retinal polyene chain (15).…”

Section: Resultsmentioning

confidence: 98%

“…However, K's Raman spectrum also shows unusually strong hydrogen out-of-plane (HOOP) lines at 811 and 957 cm 1. These lines are reminiscent of the anomalous HOOP vibrations in the resonance Raman spectrum of bathorhodopsin that are now known to be enhanced by torsional deformations of the retinal chromophore (15)(16)(17).…”

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confidence: 91%

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Resonance Raman spectra of bacteriorhodopsin's primary photoproduct: evidence for a distorted 13-cis retinal chromophore.

Braiman¹,

Mathies²

1982

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

271

196

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We have obtained the resonance Raman spectrum of bacteriorhodopsin's primary photoproduct K with a novel low-temperature spinning sample technique. Purple membrane at 77 K is illuminated with spatially separated actinic (pump) and probe laser beams. The 514-nm pump beam produces a photostationary steady-state mixture of bacteriorhodopsin and K. This mixture is then rotated through the red (676 nm) probe beam, which selectively enhances the Raman scattering from K. The essential advantage of our successive pump-and-probe technique is that it prevents the fluorescence excited by the pump beam from masldng the red probe Raman scattering. K exhibits strong Raman lines at 1516, 1294, 1194, 1012, 957, and 811 cm-'. The effects of C15 deuteration on K's fingerprint lines correlate well with those seen in 13-cis model compounds, indicating that K has a 13-cis chromophore. However, the presence of unusually strong "lowwavenumber" lines at 811 and 957 cm-, attributable to hydrogen out-of-plane wags, indicates that the protein holds the chromophore in a distorted conformation after trans-*cis isomerization. Bacteriorhodopsin (BR), the major component of the purple membrane found in Halobacterium halobium, is a retinal-containing protein that acts as a solar energy converter (1, 2). Absorption of light by retinal in light-adapted BR drives the pigment through a proton-pumping photocycle that stores energy for ATP synthesis as a trans-membrane proton gradient (3,4). In order to understand the mechanism of this light-driven proton pump, we have been studying the structure of the parent BR molecule and its photoproducts ( Fig. 1) with resonance Raman spectroscopy.Raman spectra provide detailed vibrational information about chromophore structure (5-8) that is particularly useful when aided by selective isotopic modification ofretinal because these substitutions permit unambiguous characterization of the molecular vibrations. For example, we have recently shown that the 15-deuterio-induced changes in the 1100-1300 cm-' fingerprint vibrations ofthe chromophore provide a clear criterion for distinguishing between the 13-cis and all-trans configurations even in the presence ofprotein perturbations (9). We have used this method to show that the M412 intermediate contains a 13-cis retinal chromophore, whereas the parent BR chromophore is all-trans, in agreement with the most recent chromophore extraction results (10,11).This in situ demonstration of a trans--cis isomerization during proton pumping has focused our attention on K, the primary photoproduct in the proton-pumping cycle. Arguments based on analogies between the photochemical behavior of rhodopsin and BR (12), when coupled with the Raman and extraction results on M412 (7-11), suggest that the primary photochemical

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Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 98%

See 1 more Smart Citation

Resonance Raman spectra of bacteriorhodopsin's primary photoproduct: evidence for a distorted 13-cis retinal chromophore.

Braiman¹,

Mathies²

1982

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

271

196

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“…In any case, this notion that hydrogen-bonding strength to a -CdNH-group affects its shift in frequency upon deuteration is well established in other systems. 17, [22][23][24][25][26] To determine whether the C6dN5H stretch frequency and its deuterium shift can be related with the hydrogen-bonding strength on the CdNH moiety, we have conducted systematic calculations mostly on the C6-C9 anti, 4-oxy, N5 protonated H 2 pterin/water complex with water oxygen fixed at varying distances from N5. This model has been chosen in our calculations because no counterion is expected in the immediate vicinity of N5 in either aqueous solution or in the DHFR ternary complex, and the complication due to the interaction between N10 and N5 can be separated.…”

Section: Resultsmentioning

confidence: 99%

Structure of Dihydrofolate When Bound to Dihydrofolate Reductase

Deng

Callender

1998

J. Am. Chem. Soc.

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The Raman spectrum of dihydrofolate (H 2 folate) complexed with dihydrofolate reductase (DHFR) and NADP + , believed to be an accurate mimic of the productive DHFR/NADPH/H 2 folate complex involved in the reaction catalyzed by DHFR, contains bands associated with stretch motions of N5dC6 of bound substrate. However, the assignments of these bands, which are of considerable importance to understanding enzymic mechanism and substrate binding, are in doubt. The vibrational spectra of dihydrofolate, alone and complexed with water and with acetate, have been calculated using quantum mechanical ab initio procedures in order to assign the observed bands. Several structural conclusions follow from these calculations. N5 of H 2 folate when bound to DHFR/NADP + has a pK a of 6.5. From an examination of deuteration shifts, the immediate environment of N5 of substrate is quite hydrophobic; there does not appears to be an immediate water molecule near enough to form a hydrogen bond with a protonated N5-H. It is suggested that the carboxyl group of Asp27, the only ionizable group in the DHFR binding site, is ionized at physiological pH values and does not donate a proton to substrate during enzymic catalysis. Overall, the results suggest that a major structural attribute of DHFR is to raise the pK a of N5 4 units when H 2 folate binds in the productive ground-state ternary complex. Such a strategy would appear to be responsible for a substantial portion of the rate enhancement in the reaction catalyzed by DHFR.

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“…94 The HOOP band gains its intensity when the polyene chain is distorted. 108 In fact, no intense HOOP band was observed for polyenes in solution because the polyene quickly adopts the stable planar form following photoisomerization in solution. A distorted polyene chain with a measurable lifetime in the protein would be due to a highly packed structure around the retinal.…”

Section: Dynamics Of Photoreceptor Proteins (Protein Dynamics Inducedmentioning

confidence: 99%

Time-Resolved Resonance Raman Spectroscopy and Application to Studies on Ultrafast Protein Dynamics

Mizutani

2017

Bulletin of the Chemical Society of Japan

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Protein dynamics play a fundamental role in allosteric regulation, which is vital to the function of many proteins. In many proteins, rather than a direct interaction, mutual modulation of properties such as ligand affinity at spatially separated sites is achieved through a conformational change. Conformational changes of proteins are thermally activated processes that involve intramolecular and intermolecular energy exchanges. In this account, I review the work of my team on the development and applications of ultrafast time-resolved resonance Raman spectroscopy to observe functionally important protein dynamics. We gained insights into conformational dynamics upon external stimulus and energy flow with a spatial resolution of a single amino acid residue using time-resolved visible and ultraviolet resonance Raman spectroscopy. The results have contributed to a deeper understanding of the structural nature of protein motion and the relationship of dynamics to function. I discuss the protein dynamics and allosteric mechanism in terms of the nature of the high packing density of protein structures. In addition, I present a view of the future of molecular science on proteins.

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Assignment of the anomalous resonance Raman vibrations of bathorhodopsin

Cited by 41 publications

References 1 publication

Resonance Raman spectra of bacteriorhodopsin's primary photoproduct: evidence for a distorted 13-cis retinal chromophore.

Resonance Raman spectra of bacteriorhodopsin's primary photoproduct: evidence for a distorted 13-cis retinal chromophore.

Structure of Dihydrofolate When Bound to Dihydrofolate Reductase

Time-Resolved Resonance Raman Spectroscopy and Application to Studies on Ultrafast Protein Dynamics

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