The Increase in the Peroxidase Activity of the Cytochrome with Substitutions in the Universal Binding Site Is Associated with Changes in the Ability to Interact with External Ligands.

Cytochrome (CytC), a one-electron carrier, transfers electrons from complex to cytochrome oxidase (CcO) in the electron-transport chain. Electrostatic interaction with the partners, complex and CcO, is ensured by a lysine cluster near the heme forming the Universal Binding Site (UBS). We constructed three mutant variants of mitochondrial CytC with one (2Mut), four (5Mut), and five (8Mut) Lys->Glu substitutions in the UBS and some compensating Glu->Lys substitutions at the periphery of the UBS for charge compensation.

Lel A. Drachev and the Direct Electrometric Method.

In the bioenergetics studies, the direct electrometric method played an important role. This method is based on measuring the electrical potential difference (Δψ) between two compartments of the experimental cell generated by some membrane proteins. These proteins are incorporated into closed lipid-protein membrane vesicles associated with an artificial lipid membrane that separates the compartments.

The Photoprotective Protein PsbS from Green Microalga : The Amino Acid Sequence, 3D Structure and Probable pH-Sensitive Residues.

PsbS is one of the key photoprotective proteins, ensuring the tolerance of the photosynthetic apparatus (PSA) of a plant to abrupt changes in irradiance. Being a component of photosystem II, it provides the formation of quenching centers for excited states of chlorophyll in the photosynthetic antenna with an excess of light energy. The signal for "turning on" the photoprotective function of the protein is an excessive decrease in pH in the thylakoid lumen occurring when all the absorbed light energy (stored in the form of transmembrane proton potential) cannot be used for carbon assimilation.

Mutant Cytochrome C as a Potential Detector of Superoxide Generation: Effect of Mutations on the Function and Properties.

Cytochrome c (CytC) is a single-electron carrier between complex bc1 and cytochrome c-oxidase (CcO) in the electron transport chain (ETC). It is also known as a good radical scavenger but its participation in electron flow through the ETC makes it impossible to use CytC as a radical sensor. To solve this problem, a series of mutants were constructed with substitutions of Lys residues in the universal binding site (UBS) which interact electrostatically with negatively charged Asp and Glu residues at the binding sites of CytC partners, bc1 complex and CcO.

Biologist Nikolai K. Koltzoff: the forgotten genius.

Nikolai K. Koltzoff (Koltsov) (1872-1940) is one of the key figures in Russian biology. He essentially initiated Russian physicochemical biology and established a large scientific school in the area.

Chilling Upregulates Expression of the PsbS and LhcSR Genes in the Chloroplasts of the Green Microalga Lobosphaera incisa IPPAS C-2047.

Non-photochemical quenching (NPQ) of excited chlorophyll states is essential for protecting the photosynthetic apparatus (PSA) from the excessive light-induced damage in all groups of oxygenic photosynthetic organisms. The key component of the NPQ mechanism in green algae and some other groups of algae and mosses is the LhcSR protein of the light harvesting complex (LHC) protein superfamily. In vascular plants, LhcSR is replaced by PsbS, another member of the LHC superfamily and a subunit of photosystem II (PSII).

A Review of the Dawn of Benchtop EPR Spectrometers-Innovation That Shaped the Future of This Technology.

By the early 1980s, unique devices appeared in the USSR: a series of benchtop specialized EPR spectrometers. This equipment was quickly accepted not only in science but also in medicine and in many technical and economic areas including chemical industries and geologic exploration. The appearance of these devices was perceived as a salvation for the Soviet magnetic resonance (MR) scientific instrumentation by those who worked in the field of EPR spectroscopy in the USSR.

The Effect of Chilling on the Photosynthetic Apparatus of Microalga Lobosphaera incisa IPPAS C-2047.

Photosynthetic organisms have developed a set of mechanisms aimed at preventing photo-oxidative reactions in the photosynthetic apparatus (PSA) initiated by excessively absorbed light energy. Along with high irradiance, other stressors, e.g.

The pushback against state interference in science: how Lysenkoism tried to suppress Genetics and how it was eventually defeated.

Genetics in the Soviet Union (USSR) achieved state-of-the-art results and had reached a peak of development by the mid-1930s due to the efforts of the scientific schools of several major figures, including Sergei Navashin, Nikolai Koltsov, Grigorii Levitsky, Yuri Filipchenko, Nikolai Vavilov, and Solomon Levit. Unfortunately, the Soviet government distrusted intellectually independent science and this led to state support for a fraudulent pseudoscientific concept widely known as Lysenkoism, which hugely damaged biology as a whole. Decades of dominance of the Lysenkoism had ruinous effects and the revival of biology in the USSR in the late 1950s-early 1960s was very difficult.

Electric Cables of Living Cells. II. Bacterial Electron Conductors.

The concept of "electric cables" involved in bioenergetic processes of a living cell was proposed half a century ago [Skulachev, V. P. (1971) Curr.

Electric Cables of Living Cells. I. Energy Transfer along Coupling Membranes.

The concept of "electric cables" involved in bioenergetic processes in a living cell was proposed half a century ago [Skulachev, V. P. (1971) Curr.

Senescence and entrenchment in evolution of amino acid sites.

Amino acid propensities at a site change in the course of protein evolution. This may happen for two reasons. Changes may be triggered by substitutions at epistatically interacting sites elsewhere in the genome.

Spectrum of Light as a Determinant of Plant Functioning: A Historical Perspective.

The significance of the spectral composition of light for growth and other physiological functions of plants moved to the focus of "plant science" soon after the discovery of photosynthesis, if not earlier. The research in this field recently intensified due to the explosive development of computer-controlled systems for artificial illumination and documenting photosynthetic activity. The progress is also substantiated by recent insights into the molecular mechanisms of photo-regulation of assorted physiological functions in plants mediated by photoreceptors and other pigment systems.

Allele-specific nonstationarity in evolution of influenza A virus surface proteins.

Influenza A virus (IAV) is a major public health problem and a pandemic threat. Its evolution is largely driven by diversifying positive selection so that relative fitness of different amino acid variants changes with time due to changes in herd immunity or genomic context, and novel amino acid variants attain fitness advantage. Here, we hypothesize that diversifying selection also has another manifestation: the fitness associated with a particular amino acid variant should decline with time since its origin, as the herd immunity adapts to it.

Cationic penetrating antioxidants switch off Mn cluster of photosystem II in situ.

Mitochondria-targeted antioxidants (also known as 'Skulachev Ions' electrophoretically accumulated by mitochondria) exert anti-ageing and ROS-protecting effects well documented in animal and human cells. However, their effects on chloroplast in photosynthetic cells and corresponding mechanisms are scarcely known. For the first time, we describe a dramatic quenching effect of (10-(6-plastoquinonyl)decyl triphenylphosphonium (SkQ1) on chlorophyll fluorescence, apparently mediated by redox interaction of SkQ1 with Mn cluster in Photosystem II (PSII) of chlorophyte microalga Chlorella vulgaris and disabling the oxygen-evolving complex (OEC).

Tradescantia-based models: a powerful looking glass for investigation of photoacclimation and photoadaptation in plants.

Here, we summarize diverse evidence from species that belong to the genus Tradescantia, which we propose as handy and versatile models for studies of the ecology of photosynthesis and the mechanisms of photoacclimation in higher plants. A valuable feature of this genus is the amazingly broad range of ecological niches occupied by its species: from shady understory of tropical rainforest to deserts and semideserts. The former habitats demand shade tolerance (e.

Reorganization energies of the electron transfer reactions involving quinones in the reaction center of Rhodobacter sphaeroides.

In framework of the continuum electrostatics theory, the reorganization energies of the electron transfers Q-Q (fast phase), Bph-Q, P-Q, and P-Q in the photosynthetic bacterial reaction center have been calculated. The calculations were based on the static dielectric permittivity spatial distribution derived from the data on the electrogenesis, with the corresponding characteristic times relatively close to the reaction times of Q-Q (fast phase) and Bph-Q but much shorter than those times of the latter two recombination reactions. The calculated reorganization energies were reasonably close to the experimental estimates for Q-Q (fast phase) and Bph-Q but substantially lower than those of P-Q and P-Q.

Effect of Ca on the redox potential of heme a in cytochrome c oxidase.

Subunit I of cytochrome c oxidase (CcO) from mitochondria and many bacteria contains a cation binding site (CBS) located at the outer positively charged aqueous phase not far from heme a. Binding of Ca with the CBS in bovine CcO inhibits activity of the enzyme 2-3 -fold [Vygodina, T., Kirichenko, A.

Three phases of energy-dependent induction of [Formula: see text] and Chl a fluorescence in Tradescantia fluminensis leaves.

In plants, the short-term regulation (STR, seconds to minute time scale) of photosynthetic apparatus is associated with the energy-dependent control in the chloroplast electron transport, the distribution of light energy between photosystems (PS) II and I, activation/deactivation of the Calvin-Benson cycle (CBC) enzymes, and relocation of chloroplasts within the plant cell. In this work, using a dual-PAM technique for measuring the time-courses of P photooxidation and Chl a fluorescence, we have investigated the STR events in Tradescantia fluminensis leaves. The comparison of Chl a fluorescence and [Formula: see text] induction allowed us to investigate the contribution of the trans-thylakoid pH difference (ΔpH) to the STR events.

EPR in the USSR: the thorny path from birth to biological and chemical applications.

In 1944, electron paramagnetic resonance (EPR) was discovered by Evgenii Konstantinovich Zavoisky in the USSR (Union of the Soviet Socialist Republics). Since then, magnetic resonance methods have contributed invaluably to our knowledge in many areas of Life Sciences and Chemistry, and particularly in the area of photosynthesis research. However, the road of the magnetic resonance methods, as well as its acceptance in Life Sciences and Chemistry, was not smooth and prompt in the (former) USSR.

Analysis of Photoprotection and Apparent Non-photochemical Quenching of Chlorophyll Fluorescence in Tradescantia Leaves Based on the Rate of Irradiance-Induced Changes in Optical Transparence.

The kinetics of irradiation-induced changes in leaf optical transparence (ΔT) and non-photochemical quenching (NPQ) of chlorophyll fluorescence in Tradescantia fluminensis and T. sillamontana leaves adapted to different irradiance in nature was analyzed. Characteristic times of a photoinduced increase and a dark decline of ΔT in these species were 12 and 20 min, respectively.

Tolerance of the Photosynthetic Apparatus to Acidification of the Growth Medium as a Possible Determinant of CO-Tolerance of the Symbiotic Microalga Desmodesmus sp. IPPAS-2014.

The symbiotic unicellular chlorophyte Desmodesmus sp. IPPAS-2014 capable of growth at extremely high CO2 levels prohibitive for most other microalgae is an interesting model for studies of CO2 tolerance mechanisms and a promising organism for CO2 biocapture. We studied the initial (0-60 min) phase of acclimation of this microalga to an abrupt decrease in pH of the medium sparged with air/20% CO2 mixture.

Acclimation of shade-tolerant and light-resistant Tradescantia species to growth light: chlorophyll a fluorescence, electron transport, and xanthophyll content.

In this study, we have compared the photosynthetic characteristics of two contrasting species of Tradescantia plants, T. fluminensis (shade-tolerant species), and T. sillamontana (light-resistant species), grown under the low light (LL, 50-125 µmol photons m s) or high light (HL, 875-1000 µmol photons m s) conditions during their entire growth period.

The Chloroplast Proteome Changes in Response to Protoplastation.

Plant protoplasts are widely used for genetic manipulation and functional studies in transient expression systems. However, little is known about the molecular pathways involved in a cell response to the combined stress factors resulted from protoplast generation. Plants often face more than one type of stress at a time, and how plants respond to combined stress factors is therefore of great interest.