Purple membranes (PM) from Halobacterium halobium were incorporated into 7.5% polyacrylamide gels to prevent aggregation which occurs in suspensions at low pH. At pH 7.0, the circular dichroism (CD) spectra and visible absorption spectra of light- and dark-adapted bacteriorhodopsin (bR558, respectively) and the flash photolysis cycle of bR568 in gels were essentially the same as those in PM suspensions. Titration of the gels with hydrochloric acid showed the transition to a form absorbing at 605 nm (bR605 acid) with pK = 2.9 and to a second form absorbing at 565 nm (bR565 acid) with pK = 0.5. Isosbestic points were seen for each transition in both light- and dark-adapted gels. In addition, a third isosbestic point was evident between pH 3.5 and 7. Visible CD spectra of bR568, bR605 acid, and bR565 acid all showed the bilobed pattern typical of bR568 in suspensions of PM. Flash kinetic spectrophotometry (with 40-microseconds time resolution) of bR605 acid and bR565 acid showed transient absorbance changes with at least one transiently blue-shifted form for each and an early red-shifted intermediate for bR565 acid. Chromophore extraction from membrane suspensions yielded all-trans-retinal for bR565 acid and a mixture of 13-cis an...Continue Reading
Kinetics and stoichiometry of light-induced proton release and uptake from purple membrane fragments, Halobacterium halobium cell envelopes, and phospholipid vesicles containing oriented purple membrane
A natural CD label to probe the structure of the purple membrane from Halobacterium halobium by means of exciton coupling effects
Reversible dissociation of the purple complex in bacteriorhodopsin and identification of 13-cis and all-trans-retinal as its chromophores
Influence of the size and protonation state of acidic residue 85 on the absorption spectrum and photoreaction of the bacteriorhodopsin chromophore
Differences between the photocycles of halorhodopsin and the acid purple form of bacteriorhodopsin analyzed with millisecond time-resolved FTIR spectroscopy
Effect of beta-particles on the retinal chromophore in bacteriorhodopsin of Halobacterium salinarium
Photochemical conversion of the O-intermediate to 9-cis-retinal-containing products in bacteriorhodopsin films
A comparison of the second harmonic generation from light-adapted, dark-adapted, blue, and acid purple membrane
Involvement of two groups in reversal of the bathochromic shift of pharaonis phoborhodopsin by chloride at low pH
Aspartate-histidine interaction in the retinal schiff base counterion of the light-driven proton pump of Exiguobacterium sibiricum
Photochemical and thermal stability of green and blue proteorhodopsins: implications for protein-based bioelectronic devices
pH-Sensitive photoinduced energy transfer from bacteriorhodopsin to single-walled carbon nanotubes in SWNT-bR hybrids
Importance of bound divalent cations to the tyrosine deprotonation during the photocycle of bacteriorhodopsin
On the molecular mechanisms of the Schiff base deprotonation during the bacteriorhodopsin photocycle
Evidence for the involvement of more than one metal cation in the Schiff base deprotonation process during the photocycle of bacteriorhodopsin
Tryptophan fluorescence quenching as a monitor for the protein conformation changes occurring during the photocycle of bacteriorhodopsin under different perturbations
Effect of genetic modification of tyrosine-185 on the proton pump and the blue-to-purple transition in bacteriorhodopsin
Uv-visible spectroscopy of bacteriorhodopsin mutants: substitution of Arg-82, Asp-85, Tyr-185, and Asp-212 results in abnormal light-dark adaptation
Protonation state of Asp (Glu)-85 regulates the purple-to-blue transition in bacteriorhodopsin mutants Arg-82----Ala and Asp-85----Glu: the blue form is inactive in proton translocation
Binding of a single divalent cation directly correlates with the blue-to-purple transition in bacteriorhodopsin
Kinetic and spectroscopic effects of protein-chromophore electrostatic interactions in bacteriorhodopsin
Mutation of arginine 134 to lysine alters the pK(a)s of key groups involved in proton pumping by bacteriorhodopsin
Effects of substitutions D73E, D73N, D103N and V106M on signaling and pH titration of sensory rhodopsin II
Effect of substitution of proline-77 to aspartate on the light-driven proton release of bacteriorhodopsin
Probing a polar cluster in the retinal binding pocket of bacteriorhodopsin by a chemical design approach
Photocurrent from oriented membrane films containing acid-blue and acid-purple bacteriorhodopsin and its mutants
Photocycle of Exiguobacterium sibiricum rhodopsin characterized by low-temperature trapping in the IR and time-resolved studies in the visible
Cl- -dependent photovoltage responses of bacteriorhodopsin: comparison of the D85T and D85S mutants and wild-type acid purple form
Titration kinetics of Asp-85 in bacteriorhodopsin: exclusion of the retinal pocket as the color-controlling cation binding site
Proteoliposomes with right-side-out oriented purple membrane/bacteriorhodopsin require cations inside for proton pumping
Comparison of the O640 photo-intermediate and acid-induced species in membrane patches from Halobacterium halobium S9 and R1 mW strains
Photochromic bacteriorhodopsin mutant with high holographic efficiency and enhanced stability via a putative self-repair mechanism
Proton movement in reconstituted purple membrane of halobacteria: effects of pH and ionic composition of the medium
Influence of cation binding on the electro-optically determined electric moments of purple membranes
On the protein residues that control the yield and kinetics of O(630) in the photocycle of bacteriorhodopsin
Suppressed or recovered intensities analysis in site-directed (13)C NMR: assessment of low-frequency fluctuations in bacteriorhodopsin and D85N mutants revisited
Archaerhodopsin-2, from Halobacterium sp. aus-2 further reveals essential amino acid residues for light-driven proton pumps
The primary photoreaction of channelrhodopsin-1: wavelength dependent photoreactions induced by ground-state heterogeneity
Location of a cation-binding site in the loop between helices F and G of bacteriorhodopsin as studied by 13C NMR
Experimental and theoretical characterization of the high-affinity cation-binding site of the purple membrane
Proton transfer reactions in native and deionized bacteriorhodopsin upon delipidation and monomerization
Photochemistry in dried polymer films incorporating the deionized blue membrane form of bacteriorhodopsin
Fourier transform infrared study of the effect of different cations on bacteriorhodopsin protein thermal stability
Nature of the chromophore binding site of bacteriorhodopsin: the potential role of Arg82 as a principal counterion
Weakened coupling of conserved arginine to the proteorhodopsin chromophore and its counterion implies structural differences from bacteriorhodopsin
Cyanobacterial light-driven proton pump, gloeobacter rhodopsin: complementarity between rhodopsin-based energy production and photosynthesis
Crystal structure of Halobacterium salinarum halorhodopsin with a partially depopulated primary chloride-binding site
Formation of 9-cis- and 11-cis-retinal pigments from bacteriorhodopsin by irradiating purple membrane in acid
The purple to blue transition of bacteriorhodopsin is accompanied by a loss of the hexagonal lattice and a conformational change
Substitution of membrane-embedded aspartic acids in bacteriorhodopsin causes specific changes in different steps of the photochemical cycle
Effect of a light-induced pH gradient on purple-to-blue and purple-to-red transitions of bacteriorhodopsin
Wild-type and mutant bacteriorhodopsins D85N, D96N, and R82Q: purification to homogeneity, pH dependence of pumping, and electron diffraction
Effect of the arginine-82 to alanine mutation in bacteriorhodopsin on dark adaptation, proton release, and the photochemical cycle
Effect of specific carboxyl modifications on the blue acid species and O650 photocycle intermediate of bacteriorhodopsin
The role of the native lipids and lattice structure in bacteriorhodopsin protein conformation and stability as studied by temperature-dependent Fourier transform-infrared spectroscopy
Studies on the temperature effect on bacteriorhodopsin of purple and blue membrane by fluorescence and absorption spectroscopy
Absorption spectra of benzoic acid in water at different pH and in the presence of salts: insights from the integration of experimental data and theoretical cluster models
Contribution of extracellular Glu residues to the structure and function of bacteriorhodopsin. Presence of specific cation-binding sites
Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.
Synthetic Genetic Array Analysis
Synthetic genetic arrays allow the systematic examination of genetic interactions. Here is the latest research focusing on synthetic genetic arrays and their analyses.
Congenital hyperinsulinism is caused by genetic mutations resulting in excess insulin secretion from beta cells of the pancreas. Here is the latest research.
Neural Activity: Imaging
Imaging of neural activity in vivo has developed rapidly recently with the advancement of fluorescence microscopy, including new applications using miniaturized microscopes (miniscopes). This feed follows the progress in this growing field.
Chronic Fatigue Syndrome
Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.
Epigenetic memory refers to the heritable genetic changes that are not explained by the DNA sequence. Find the latest research on epigenetic memory here.
Cell Atlas of the Human Eye
Constructing a cell atlas of the human eye will require transcriptomic and histologic analysis over the lifespan. This understanding will aid in the study of development and disease. Find the latest research pertaining to the Cell Atlas of the Human Eye here.
Femoral Neoplasms are bone tumors that arise in the femur. Discover the latest research on femoral neoplasms here.
STING Receptor Agonists
Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.