Disease relevance of Chromatophores

• Proton transfer from the bulk to the bound ubiquinone Q(B) of the reaction center in chromatophores of Rhodobacter sphaeroides: retarded conveyance by neutral water [1].
• The interaction of 4-chloro-7-nitrobenzofurazan with Rhodospirillum rubrum chromatophores, their soluble F1-ATPase, and the isolated purified beta-subunit [2].
• The hydrolytic activity of H(+)-PPase in E. coli vesicles was eight times greater than that in R. rubrum chromatophores but exhibited similar sensitivity to the H(+)-PPase inhibitor, aminomethylenediphosphonate, and insensitivity to the soluble PPase inhibitor, fluoride [3].
• The effects of cerulenin were investigated in Rhodopseudomonas sphaeroides to elucidate further the mechanisms controlling the assembly of the chromatophore membrane [4].
• The chromatophores of Chromatium vinosum, as well as six other photosynthetic bacteria, contained two or more proteins which were insoluble when heated in the presence of sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (beta-ME) [5].

High impact information on Chromatophores

• In nature, activation of G-protein-coupled receptors expressed by skin cells called chromatophores effects pigment redistribution within the cells to change an animal's coloration [6].
• Pigment migration in cultured erythrophores of the squirrel fish Holocentrus ascensionis, after manipulation with K+, epinephrine, 3',5'-dibutyryl cyclic adenosine monophosphate, theophylline, and caffeine, is essentially identical to that observed in this chromatophore in situ [7].
• In chromatophores, the decrease in the amount of photoreducible quinones when inhibiting a fraction of the centers implies a confinement of the quinone pool over small domains, including one to six reaction centers [8].
• These two interacting regions are on the cytoplasmic side of the chromatophore membrane and closed to the DE loop and helix G of cytochrome b, respectively [9].
• A sulfide-quinone oxidoreductase (SQR, EC 1.8.5.'.) has been purified to homogeneity from chromatophores of the non-sulfur purple bacterium Rhodobacter capsulatus DSM 155 [10].

Chemical compound and disease context of Chromatophores

• Postillumination adenosine triphosphate synthesis in Rhodospirillum rubrum chromatophores. I. Conditions for maximal yields [11].
• Pyridine dinucleotide transhydrogenase of the Rhodospirillum rubrum chromatophore membrane was readily resolved by a washing procedure into two inactive components, a soluble transhydrogenase factor protein and an insoluble membrane-bound factor [12].
• Localization of chromatophore proteins of Rhodobacter sphaeroides. II. Topography of cytochrome c1 and the Rieske iron-sulfur protein as determined by proteolytic digestion of the outer and luminal membrane surfaces [13].
• 1. The absorption changes associated with the formation of P+QBred (QBred stands for the semiquinone state of the secondary quinone acceptor) were investigated in chromatophores of Rhodobacter capsulatus [14].
• DCCD inhibits the reactions of the iron-sulfur protein in Rhodobacter sphaeroides chromatophores [15].

Biological context of Chromatophores

• Photophosphorylation and ATPase activities were restored to beta-less Rhodospirillum rubrum chromatophores by their reconstitution with purified beta-subunits of either R. rubrum F1-ATPase (Rr beta) or Escherichia coli F1-ATPase (Ec beta) [16].
• Also, a rapid and unidirectional transbilayer movement of PE polar head groups from the periplasmic to cytoplasmic surfaces of the membrane appears to occur during phospholipase A2 hydrolysis on the chromatophore surfaces [17].
• The relatively membrane impermeable reagent trinitrobenzenesulfonate (TNBS) at 3 mM concentration and 5 degrees C modified chromatophore and SDV PE with kinetics indicating the occurrence of fast- and slow-reacting pools of PE [17].
• Glutamate receptor types were examined at the chromatophore synapses of the squids Alloteuthis subulata and Loligo vulgaris, where nerve-induced muscle contraction causes chromatophore expansion [18].
• In addition the restoration of electron transport in depleted chromatophores by the artificial redox compounds N-methylphenazonium methosulfate and N,N,N',N'-tetramethyl-p-phenylenediamine was studied [19].

Anatomical context of Chromatophores

• Analysis of the shapes of the semiquinone titration curves, taken together with the midpoint elevation, indicates a quinone-binding site: cytochrome c1 stoichiometry of 1:1 in both submitochondrial particles and chromatophores [20].
• By activity and immunoblot analysis of expression of translational fusions to Escherichia coli alkaline phosphatase, RnfA protein was shown to span the chromatophore membrane with its odd-numbered hydrophilic regions exposed to periplasm [21].
• Ferrochelatase was found almost exclusively in the chromatophore fraction and was located on the outer face of the chromatophores, i.e. in contact with the cytosol in intact cells [22].
• Messenger RNAs for IGFBP-3 to IGFBP-6 localized to choroidal endothelial cells and chromatophores and also to the inner pigmented epithelium of the ciliary processes [23].
• Triton extracts of intracytoplasmic photosynthetic membranes (chromatophores) purified from Rhodopseudomonas sphaeroides were subjected to crossed immunoelectrophoresis with antiserum raised in rabbits to purified chromatophores [24].

Associations of Chromatophores with chemical compounds

• Incubation of the beta-subunit with DCCD and EEDQ eliminates its capacity to rebind to beta-less chromatophores [25].
• In chromatophores in which the ubiquinone is partially extracted by isooctane (leaving 4 ubiquinones/reaction center), undecyl-HNQ is effective at 2.5 times lower concentration than in normal chromatophores (30 ubiquinones/reaction center) [26].
• Addition of valinomycin, nonactin, or monactin plus KCl in the dark to preilluminated chromatophores induced the synthesis of a large amount of ATP [27].
• The antimycin analog, 3-azidosalicyl-N-(n-octadecyl)amide, inhibited succinate-cytochrome c reductase activity in chromatophore vesicles by 50% at a concentration of 150 nmols/mg of protein [28].
• 5. Association of isolated R. rubrum chromatophores with planar phospholipid membrane was found to give a system demonstrating light-induced electric generation as high as 215 mV in the presence of napthoquinone, TMPD (or phenazine methosulfate, PMS), and ascorbate [29].

Gene context of Chromatophores

• Comparative analyses of the pigment-aggregating and -dispersing actions of MCH on fish chromatophores [30].
• In addition, glial fibrillary acidic and S-100 proteins were detected in the chromatophores with immunohistochemical staining [31].
• Cys-185 reacts with NEM only after detergent disruption of the sealed, inside-out chromatophores, indicating that this position of cytochrome b is accessible on the outer (periplasmic) surface of the membrane [32].
• Measurements of respiratory activity indicated a 1.6-fold higher level of succinate-cytochrome c oxidoreductase/reaction center than in chromatophores, but the apparent turnover rates in both preparations were low [33].
• Phospholipase A2 treatment inhibited 60% of the succinate dehydrogenase activity of chromatophores but only 8% of the activity of SDVs, indicating the membrane impermeability of phospholipase A2 [17].

Analytical, diagnostic and therapeutic context of Chromatophores

• The enzyme was solubilized from chromatophores by using dodecyl maltoside in the presence of glycerol and was purified by anion-exchange and gel filtration chromatography [34].
• Affinity chromatography of H+-translocating adenosine triphosphatase isolated by chloroform extraction of Rhodospirillum rubrum chromatophores. Modification of binding affinity by divalent cations and activating anions [35].

References