The Laser-Induced Blue State of Bacteriorhodopsin:  Mechanistic and Color Regulatory Roles of Protein−Protein Interactions, Protein−Lipid Interactions, and Metal Ions

Masthay, Mark B.; Sammeth, David M.; Helvenston, Merritt C.; Buckman, Charles B.; Li, Wuyi; Cde-Baca, Michael J.; Kofron, John T.

doi:10.1021/ja010116a

Cited by 14 publications

(23 citation statements)

References 111 publications

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“…This high quantum efficiency is identical to that of the visual photopigment, rhodopsin, which is found in the photoreceptor cells of the retina [68,69]. One of the unique features of the BR photocycle is the branched photocycle [25,[70][71][72]. During the classical photocycle of BR, the last and most red-shifted intermediate, designated as the O state, contains an all-trans configuration of the retinal chromophore ( figure 1).…”

Section: Bacteriorhodopsinmentioning

confidence: 70%

Directed evolution of bacteriorhodopsin for applications in bioelectronics

Wagner

Greco

Ranaghan

et al. 2013

J. R. Soc. Interface.

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In nature, biological systems gradually evolve through complex, algorithmic processes involving mutation and differential selection. Evolution has optimized biological macromolecules for a variety of functions to provide a comparative advantage. However, nature does not optimize molecules for use in human-made devices, as it would gain no survival advantage in such cooperation. Recent advancements in genetic engineering, most notably directed evolution, have allowed for the stepwise manipulation of the properties of living organisms, promoting the expansion of protein-based devices in nanotechnology. In this review, we highlight the use of directed evolution to optimize photoactive proteins, with an emphasis on bacteriorhodopsin (BR), for device applications. BR, a highly stable light-activated proton pump, has shown great promise in three-dimensional optical memories, real-time holographic processors and artificial retinas.

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Section: Bacteriorhodopsinmentioning

confidence: 70%

Directed evolution of bacteriorhodopsin for applications in bioelectronics

Wagner

Greco

Ranaghan

et al. 2013

J. R. Soc. Interface.

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“…Since absorption spectra of bacteriorhodopsin and its intermediates are broad (Δλ FWHM ~ 100–120 nm 14,46,47 ) and non-structured, for further analysis each measured spectrum was separately smoothed as in 48 by a sliding cubic polynomial over 20 neighboring (i.e. ±10 nm) spectral points, resulting in a data matrix (for each temperature) of 33 time-slices by 344 wavelengths.…”

Section: Experimental Methodsmentioning

confidence: 99%

Two Bathointermediates of the Bacteriorhodopsin Photocycle, from Time-Resolved Nanosecond Spectra in the Visible

Dioumaev

Lanyi

2009

J. Phys. Chem. B

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Time-resolved measurements were performed on wild-type bacteriorhodopsin with an optical multi-channel analyzer in the spectral range of 350–735 nm, from 100 ns to the photocycle completion, at four temperatures in the 5–30 °C range. The intent was to examine the possibility of two K-like bathochromic intermediates and to obtain their spectra and kinetics in the visible. The existence of a second K-like intermediate, termed KL, had been postulated (Shichida et al., BBA 723:240–246, 1983) to reconcile inconsistencies in data in the pico- and microsecond time-domains. However, introduction of KL led to a controversy since neither its visible spectrum nor its kinetics could be confirmed. Infra-red data (Dioumaev & Braiman, J. Phys. Chem., B, 101:1655–1662, 1997), revealed a state, which might have been considered a homologue to KL but it had a kinetic pattern different from that of the earlier proposed KL. Here we characterize two distinct K-like intermediates, KE (“early”) and KL (“late”), by their spectra and kinetics in the visible as revealed by global kinetic analysis. The KE-to-KL transition has a time constant of ~250 ns at 20 °C, and describes a shift from KE with λmax at ~600 nm and extinction of ~56,000 M−1·cm−1 to KL with λmax at ~590 nm and extinction of ~50,000 M−1·cm−1. The temperature dependence of this transition is characterized by an enthalpy of activation ΔH# ~ 40 kJ/mol, and a positive entropy of activation ΔS#/R = ~4. The consequences of multiple K-like states for interpreting the spectral evolution in the early stages of the photocycle are discussed.

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“…Irradiation of BR suspension with high-intensity 532 nm laser pulses causes a nonreversible color shift to blue, and upon extended exposure a yellowish color remains. The obtained material was named laser-induced blue membrane (LIBM) (4)(5)(6)(7). Obviously LIBM has nothing in common with so-called blue membrane (8)(9)(10), which is obtained from PM, e.g., by deionization.…”

Section: Introductionmentioning

confidence: 99%

“…The latest model for the LIBM formation was published by Masthay et al (5). Upon photoexcitation of BR in the initial B state by high light intensities in a two-photon reaction or two sequential single-photon reactions, a state named P 360 is formed which absorbs maximally in the ultraviolet (UV).…”

Section: Introductionmentioning

confidence: 99%

Two-Photon Absorption of Bacteriorhodopsin: Formation of a Red-Shifted Thermally Stable Photoproduct F620

Fischer

Hampp

2005

Biophysical Journal

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By means of high-intensity 532 nm laser pulses, a photochemical conversion of the initial B(570) state of bacteriorhodopsin (BR) to a stable photoproduct absorbing maximally at approximately 620 nm in BR suspensions and at approximately 610 nm in BR films is induced. This state, which we named F(620), is photochemically further converted to a group of three products with maximal absorptions in the wavelength range from 340 nm to 380 nm, which show identical spectral properties to the so-called P(360) state reported in the literature. The photoconversion from B(570) to F(620) is most likely a resonant two-photon absorption induced step. The formation of F(620) and P(360) leads to a distinguished photo-induced permanent optical anisotropy in BR films. The spectral dependence of the photo-induced anisotropy and the anisotropy orientations at the educt (B(570)) and product (F(620)) wavelengths are strong indicators that F(620) is formed in a direct photochemical step from B(570). The chemical nature of the P(360) products probably is that of a retro-retinal containing BR, but the structural characteristics of the F(620) state are still unclear. The photo-induced permanent anisotropy induced by short laser pulses in BR films helps to better understand the photochemical pathways related to this transition, and it is interesting in view of potential applications as this feature is the molecular basis for permanent optical data storage using BR films.

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The Laser-Induced Blue State of Bacteriorhodopsin: Mechanistic and Color Regulatory Roles of Protein−Protein Interactions, Protein−Lipid Interactions, and Metal Ions

Cited by 14 publications

References 111 publications

Directed evolution of bacteriorhodopsin for applications in bioelectronics

Directed evolution of bacteriorhodopsin for applications in bioelectronics

Two Bathointermediates of the Bacteriorhodopsin Photocycle, from Time-Resolved Nanosecond Spectra in the Visible

Two-Photon Absorption of Bacteriorhodopsin: Formation of a Red-Shifted Thermally Stable Photoproduct F620

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