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Florian Richter, Ines Fonfara, Boris Bouazza, Charlotte Helene Schumacher, Majda Bratovič, Emmanuelle Charpentier, Andreas Möglich
Sensory photoreceptors have enabled non-invasive and spatiotemporal control of numerous biological processes. Photoreceptor engineering has expanded the repertoire beyond natural receptors, but to date no generally applicable strategy exists towards constructing light-regulated protein actuators of arbitrary function. We hence explored whether the homodimeric Rhodobacter sphaeroides light-oxygen-voltage (LOV) domain (RsLOV) that dissociates upon blue-light exposure can confer light sensitivity onto effector proteins, via a mechanism of light-induced functional site release...
October 15, 2016: Nucleic Acids Research
Benjamin W Arentson, Erin L Hayes, Weidong Zhu, Harkewal Singh, John J Tanner, Donald F Becker
Proline utilization A (PutA) is a bifunctional flavoenzyme with proline dehydrogenase (PRODH) and Δ(1)-pyrroline-5-carboxylate dehydrogenase domains that catalyzes the two-step oxidation of proline to glutamate. Trifunctional PutAs also have an N-terminal ribbon-helix-helix (RHH) DNA-binding domain and moonlight as autogenous transcriptional repressors of the put regulon. A unique property of trifunctional PutA is the ability to switch functions from DNA-bound repressor to membrane-associated enzyme in response to cellular nutritional needs and proline availability...
October 14, 2016: Bioscience Reports
Andrea von Zadow, Elisabeth Ignatz, Richard Pokorny, Lars-Oliver Essen, Gabriele Klug
Photolyases are efficient DNA repair enzymes that specifically repair either cyclobutane pyrimidine dimers (CPD) or (6-4) photoproducts in a light-dependent cleavage reaction. The closely related classical cryptochrome blue light photoreceptors do not repair DNA lesions, instead they are involved in regulatory processes. CryB of Rhodobacter sphaeroides was until now described as a cryptochrome that affects light-dependent and singlet oxygen-dependent gene expression and is unusual in terms of its cofactor composition...
October 14, 2016: FEBS Journal
Cosima Damiana Calvano, Giovanni Ventura, Massimo Trotta, Giuliana Bianco, Tommaso R I Cataldi, Francesco Palmisano
Bacteriochlorophyll a (BChl a), a photosynthetic pigment performing the same functions of chlorophylls in plants, features a bacteriochlorin macrocycle ring (18 π electrons) with two reduced pyrrole rings along with a hydrophobic terpenoid side chain (i.e., the phytol residue). Chlorophylls analysis by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) is not so straightforward since pheophytinization (i.e., release of the central metal ion) and cleavage of the phytol-ester linkage are invariably observed by employing protonating matrices such as 2,5-dihydroxybenzoic acid, sinapinic acid, and α-cyano-4-hydroxycinnamic acid...
October 11, 2016: Journal of the American Society for Mass Spectrometry
Nikolaos Remmas, Paraschos Melidis, Chrysoula Voltsi, Despoina Athanasiou, Spyridon Ntougias
Mature landfill leachate is a heavily-polluted wastewater due to its recalcitrant nature of organic matter, and high ammonia and salt content. Despite the moderate saline and alkaline nature of this habitat, no attention has been paid to the isolation and functional role of extremophiles in such environment. In this work, a total of 73 and 29 bacterial strains were isolated by using alkaline and saline media, respectively, while bacteria from mature landfill leachate growing in these media were enumerated as 1...
October 11, 2016: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
Lilit Gabrielyan, Lilit Hakobyan, Armen Trchounian
The aim of the present work was the study of comparative effects of Cu(II) and Ni(II) and their mixture on growth, redox potential, hydrogen (H2) yield and ATPase activity in phototrophic purple bacteria R. sphaeroides MDC6522 from Jermuk mineral spring in Armenia. It was ascertained, that Cu(2+) and Ni(2+) have different effects on bacterial specific growth rate: in the presence of 5μM Cu(2+) growth rate was ~3.2-fold lower in comparison with control (no addition), and increased ~1.5-fold in medium with 5μM Ni(2+)...
October 1, 2016: Journal of Photochemistry and Photobiology. B, Biology
Shan Wen, Hongyu Liu, Huijun He, Le Luo, Xiang Li, Guangming Zeng, Zili Zhou, Wei Lou, Chunping Yang
Two strains of photosynthetic bacteria, Rhodobacter blasticus and Rhodobacter capsulatus, were used in this work to investigate the feasibility of using photosynthetic bacteria for the treatment of anaerobically digested swine wastewater. The effects of crucial factors which influence the pollutants removal efficiency were also examined. Results showed that anaerobically digested swine wastewater could be treated effectively by photosynthetic bacteria. The treatment efficiency was significantly higher by the mixed photosynthetic bacteria than that by any unitary bacterium...
September 30, 2016: Bioresource Technology
Lijun Xi, Nenghu Qiao, Zhenchong Zhang, Laihong Yan, Fengbo Li, Jinpeng Hu, Jing Li
A novel bacterium, strain L3(T), was isolated from an activated sludge sample retrieved from a municipal wastewater treatment plant in Huangdao, China. On the basis of 16S rRNA gene sequence similarity studies, strain L3(T) was affiliated to the genus Sinorhodobacter, being most closely related to Sinorhodobacter ferrireducens (98.0 %). The 16S rRNA gene sequence similarity of strain L3(T) to other related species, Thioclava atlantica DLFJ1-1(T) (96.5 %), Rhodobacter capsulatus ATCC 11166(T) (96.3 %), Paenirhodobacter enshiensis DW2-9(T) (96...
September 30, 2016: Antonie Van Leeuwenhoek
Anna Tsargorodska, Michaël L Cartron, Cvetelin Vasilev, Goutham Kodali, Olga A Mass, Jeremy J Baumberg, P Leslie Dutton, C Neil Hunter, Päivi Törmä, Graham J Leggett
Gold nanostructure arrays exhibit surface plasmon resonances that split after attaching light harvesting complexes 1 and 2 (LH1 and LH2) from purple bacteria. The splitting is attributed to strong coupling between the localized surface plasmon resonances and excitons in the light-harvesting complexes. Wild-type and mutant LH1 and LH2 from Rhodobacter sphaeroides containing different carotenoids yield different splitting energies, demonstrating that the coupling mechanism is sensitive to the electronic states in the light harvesting complexes...
October 10, 2016: Nano Letters
Katrin M H Müller, Bork A Berghoff, Benjamin D Eisenhardt, Bernhard Remes, Gabriele Klug
The phototrophic bacterium Rhodobacter sphaeroides induces several small RNAs (sRNAs) when singlet oxygen (1O2) levels are elevated, a situation also referred to as photo-oxidative stress. An RNA-seq study identified the RSs0019 sRNA, which is renamed Pos19 (photo-oxidative stress induced sRNA 19). Pos19 is part of the RpoE regulon and consequently induced upon 1O2 and peroxide stress. The 219 nt long Pos19 transcript contains a small open reading frame (sORF) of 150 nt, which is translated in vivo. Over-expression of Pos19 results in reduced mRNA levels for several genes, of which numerous are involved in sulfur metabolism...
2016: PloS One
Pekka A Postila, Karol Kaszuba, Patryk Kuleta, Ilpo Vattulainen, Marcin Sarewicz, Artur Osyczka, Tomasz Róg
The cytochrome (cyt) bc1 complex is an integral component of the respiratory electron transfer chain sustaining the energy needs of organisms ranging from humans to bacteria. Due to its ubiquitous role in the energy metabolism, both the oxidation and reduction of the enzyme's substrate co-enzyme Q has been studied vigorously. Here, this vast amount of data is reassessed after probing the substrate reduction steps at the Qi-site of the cyt bc1 complex of Rhodobacter capsulatus using atomistic molecular dynamics simulations...
September 26, 2016: Scientific Reports
Frederic Melin, Hao Xie, Thomas Meyer, Young Ok Ahn, Robert B Gennis, Hartmut Michel, Petra Hellwig
Cytochrome cbb3 (also known as C-type) oxidases belong to the family of heme-copper terminal oxidases which couple at the end of the respiratory chain the reduction of molecular oxygen into water and the pumping of protons across the membrane. They are expressed most often at low pressure of O2 and they exhibit a low homology of sequence with the cytochrome aa3 (A-type) oxidases found in mitochondria. Their binuclear active site comprises a high-spin heme b3 associated with a CuB center. The protein also contains one low-spin heme b and 3 hemes c...
September 21, 2016: Biochimica et Biophysica Acta
Angela M Barragan, Klaus Schulten, Ilia A Solov'yov
The bc1 complex is a critical enzyme for the ATP production in photosynthesis and cellular respiration. Its biochemical function relies on the so-called Q-cycle, which is well established and operates via quinol substrates that bind inside the protein complex. Despite decades of research, the quinol-protein interaction, which initiates the Q-cycle, has not yet been completely described. Furthermore, the initial charge transfer reactions of the Q-cycle lack a physical description. The present investigation utilizes classical molecular dynamics simulations in tandem with quantum density functional theory calculations, to provide a complete and consistent quantitative description of the primary events that occur within the bc1 complex upon quinol binding...
October 12, 2016: Journal of Physical Chemistry. B
Eugeny P Lukashev, Petr P Knox, Vladimir V Gorokhov, Nadezda P Grishanova, Nuranija Kh Seifullina, Maria Krikunova, Heiko Lokstein, Vladimir Z Paschenko
Quantum dots (QDs) absorb ultraviolet and long-wavelength visible light energy much more efficiently than natural bacterial light-harvesting proteins and can transfer the excitation energy to photosynthetic reaction centers (RCs). Inclusion of RCs combined with QDs as antennae into liposomes opens new opportunities for using such hybrid systems as a basis for artificial energy-transforming devices that potentially can operate with greater efficiency and stability than devices based only on biological components or inorganic components alone...
September 12, 2016: Journal of Photochemistry and Photobiology. B, Biology
Vincenzo De Leo, Lucia Catucci, A Evelyn Di Mauro, Angela Agostiano, Livia Giotta, Massimo Trotta, Francesco Milano
Ultrasounds are used in many industrial, medical and research applications. Properties and function of proteins are strongly influenced by the interaction with the ultrasonic waves and their bioactivity can be lost because of alteration of protein structure. Surprisingly, to the best of our knowledge no study was carried out on Integral Membrane Proteins (IMPs), which are responsible for a variety of fundamental biological functions. In this work, the photosynthetic Reaction Center (RC) of the bacterium Rhodobacter sphaeroides has been used as a model for the study of the ultrasound-induced IMP denaturation...
September 7, 2016: Ultrasonics Sonochemistry
Melih Sener, Johan Strumpfer, Abhishek Singharoy, C Neil Hunter, Klaus Schulten
The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state...
2016: ELife
Cristina Takacs-Vesbach, Kayla King, David Van Horn, Katelyn Larkin, Maurine Neiman
Different reproductive strategies and the transition to asexuality can be associated with microbial symbionts. Whether such a link exists within mollusks has never been evaluated. We took the first steps towards addressing this possibility by performing pyrosequencing of bacterial 16S rRNA genes associated with Potamopyrgus antipodarum, a New Zealand freshwater snail. A diverse set of 60 tissue collections from P. antipodarum that were genetically and geographically distinct and either obligately sexual or asexual were included, which allowed us to evaluate whether reproductive mode was associated with a particular bacterial community...
2016: PloS One
Francesco Francia, Marco Malferrari, Pascal Lanciano, Stefan Steimle, Fevzi Daldal, Giovanni Venturoli
The ubiquinol:cytochrome (cyt) c oxidoreductase (or cyt bc1) is an important membrane protein complex in photosynthetic and respiratory energy transduction. In bacteria such as Rhodobacter capsulatus it is constituted of three subunits: the iron-sulfur protein, cyt b and cyt c1, which form two catalytic domains, the Qo (hydroquinone (QH2) oxidation) and Qi (quinone (Q) reduction) sites. At the Qo site, the pathways of bifurcated electron transfers emanating from QH2 oxidation are known, but the associated proton release routes are not well defined...
August 18, 2016: Biochimica et Biophysica Acta
Matt S A Wecker, Stephen Beaton, Robert Chado, Maria L Ghirardi
The photosynthetic bacterium Rhodobacter capsulatus normally photoproduces H2 as a by-product of its nitrogenase-catalyzed nitrogen-fixing activity. Such H2 production, however, is expensive from a metabolic perspective, requiring nearly four times as many photons as the equivalent algal hydrogenase-based system (Ghirardi et al. 2009). Here we report the insertion of a Clostridium acetobutylicum [FeFe]-hydrogenase and its three attendant hydrogenase assembly proteins into an R. capsulatus strain lacking its native uptake hydrogenase...
August 17, 2016: Biotechnology and Bioengineering
Arvi Freiberg, Manoop Chenchiliyan, Margus Rätsep, Kõu Timpmann
In the present work, spectral and kinetic changes accompanying the assembly of the light-harvesting 1 (LH1) complex with the reaction center (RC) complex into monomeric RC-LH1 and dimeric RC-LH1-PufX core complexes of the photosynthetic purple bacterium Rhodobacter sphaeroides are systematically studied over the temperature range of 4.5-300K. The samples were interrogated with a combination of optical absorption, hole burning, fluorescence excitation, steady state and picosecond time resolved fluorescence spectroscopy...
August 8, 2016: Biochimica et Biophysica Acta
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