Structure-function study of two new middle-redox potential laccases from basidiomycetes Antrodiella faginea and Steccherinum murashkinskyi.

Laccases are multicopper oxidases that catalyze oxidation of a wide range of organic and inorganic substrates accompanied by the reduction of dioxygen to water. The physicochemical and catalytic properties of two new fungal laccases from basidiomycetes Antrodiella faginea (AfL) and Steccherinum murashkinskyi (SmL) with middle redox potential of the T1 copper site were studied. The X-ray structures of AfL and SmL were solved at 1.

White-rot basidiomycetes Junghuhnia nitida and Steccherinum bourdotii: Oxidative potential and laccase properties in comparison with Trametes hirsuta and Coriolopsis caperata.

White-rot basidiomycetes from the poorly studied residual polyporoid clade of Polyporales order Junghuhnia nitida (Pers.) Ryvarden and Steccherinum bourdotii Saliba & A. David grow as secondary xylotrohps on well decomposed woody materials.

Dissection of the deep-blue autofluorescence changes accompanying amyloid fibrillation.

Pathogenesis of numerous diseases is associated with the formation of amyloid fibrils. Extrinsic fluorescent dyes, including Thioflavin T (ThT), are used to follow the fibrillation kinetics. It has recently been reported that the so-called deep-blue autofluorescence (dbAF) is changing during the aggregation process.

Discovery of a new Pro-Pro endopeptidase, PPEP-2, provides mechanistic insights into the differences in substrate specificity within the PPEP family.

Pro-Pro endopeptidases (PPEPs) belong to a recently discovered family of proteases capable of hydrolyzing a Pro-Pro bond. The first member from the bacterial pathogen (PPEP-1) cleaves two cell-surface proteins involved in adhesion, one of which is encoded by the gene adjacent to the gene. However, related PPEPs may exist in other bacteria and may shed light on substrate specificity in this enzyme family.

Changes of and /NF-B Expression Levels Induced by Cell-Free DNA in Different Cell Types.

Cell-free DNA (cfDNA) is a circulating DNA of nuclear and mitochondrial origin mainly derived from dying cells. Recent studies have shown that cfDNA is a stress signaling DAMP (damage-associated molecular pattern) molecule. We report here that the expression profiles of cfDNA-induced factors NRF2 and NF-B are distinct depending on the target cell's type and the GC-content and oxidation rate of the cfDNA.

Orchestration of the expression of the laccase multigene family in white-rot basidiomycete Trametes hirsuta 072: Evidences of transcription level subfunctionalization.

Laccase (benzenediol:oxygen oxidoreductase, EC 1.10.3.

Enhancement of lateral flow immunoassay by alkaline phosphatase: a simple and highly sensitive test for potato virus X.

Alkaline phosphatase (ALP) was used as an amplification tool in lateral flow immunoassay (LFIA). Potato virus Х (PVX) was selected as a target analyte because of its high economic importance. Two conjugates of gold nanoparticles were applied, one with mouse monoclonal antibody against PVX and one with ALP-labeled antibody against mouse IgG.

Functional interaction of low-homology FRPs from different cyanobacteria with Synechocystis OCP.

Photosynthesis requires a balance between efficient light harvesting and protection against photodamage. The cyanobacterial photoprotection system uniquely relies on the functioning of the photoactive orange carotenoid protein (OCP) that under intense illumination provides fluorescence quenching of the light-harvesting antenna complexes, phycobilisomes. The recently identified fluorescence recovery protein (FRP) binds to the photoactivated OCP and accelerates its relaxation into the basal form, completing the regulatory circle.

Dinitrosyl iron complexes: Formation and antiradical action in heart mitochondria.

Mitochondria are widely known as a major source of reactive oxygen and nitrogen species for the cardiovascular system. Numerous studies established that superoxide anion radical production by heart mitochondria is only slightly suppressed under conditions of deep hypoxia, but is completely blocked under anoxia. It was found also that dinitrosyl iron complexes (DNIC) compare favourably with other physiologically active derivatives of nitric oxide (NO).

Effect of the NBD-group position on interaction of fluorescently-labeled cholesterol analogues with human steroidogenic acute regulatory protein STARD1.

Steroidogenic acute regulatory protein (StAR, STARD1) is a key factor of intracellular cholesterol transfer to mitochondria, necessary for adrenal and gonadal steroidogenesis, and is an archetypal member of the START protein family. Despite the common overall structural fold, START members differ in their binding selectivity toward various lipid ligands, but the lack of direct structural information hinders complete understanding of the binding process and cholesterol orientation in the STARD1 complex in particular. Cholesterol binding has been widely studied by commercially available fluorescent steroids, but the effect of the fluorescent group position on binding remained underexplored.

Double-enhanced lateral flow immunoassay for potato virus X based on a combination of magnetic and gold nanoparticles.

This study presents the joint use of magnetic nanoparticles (MNPs) and gold nanoparticles (GNPs) for double enhancement in a lateral flow immunoassay (LFIA). The study realizes two types of enhancement: (1) increasing the concentration of analytes in the samples using conjugates of MNPs with specific antibodies and (2) increasing the visibility of the label through MNP aggregation caused by GNPs. The proposed strategy was implemented using a LFIA for potato virus X (PVX), a significant potato pathogen.

Four Hapten Spacer Sites Modulating Class Specificity: Nondirectional Multianalyte Immunoassay for 31 β-Agonists and Analogues.

Immunoassay methods are important for monitoring β-agonists illegally used for reducing animal fat deposition in livestock. However, there is no simultaneous screening surveillance immunoassay for detecting various β-agonist chemicals that are possibly present in food. In this study, through the use of an R-(-)-salbutamol derivative as the immunizing hapten, an antibody recognizing 31 β-agonists and analogues was generated for the first time.

Multiplex highly sensitive immunochromatographic assay based on the use of nonprocessed antisera.

The format of an immunochromatographic multiassay is first proposed with native antisera and a universal conjugate of antispecies antibodies with gold nanoparticles. This format allows (1) the exclusion of purification and conjugation stages for specific antibodies and (2) significant reduction of the concentration of specific antibodies in the system. The independent use of specific antibodies and a conjugated marker provided a low detection limit and high signal intensity.

Ultrasensitive electrochemical immuno-sensing platform based on gold nanoparticles triggering chlorpyrifos detection in fruits and vegetables.

Chlorpyrifos (chl) is an organophosphate pesticide extensively used in agriculture and highly toxic for human health. Fluorine doped tin-oxide (FTO) based electrochemical nanosensor was developed for chlorpyrifos detection with gold nanoparticles (AuNPs) and anti-chlorpyrifos antibodies (chl-Ab). AuNPs provides high electrical conductivity and specific resistivity, thus increases the sensitivity of immunoassay.

Analysis of the interactions between GMF and Arp2/3 complex in two binding sites by molecular dynamics simulation.

The Arp2/3 complex plays a key role in nucleating actin filaments branching. The glia maturation factor (GMF) competes with activators for interacting with the Arp2/3 complex and initiates the debranching of actin filaments. In this study, we performed a comparative analysis of interactions between GMF and the Arp2/3 complex and identified new amino acid residues involved in GMF binding to the Arp2/3 complex at two separate sites, revealed by X-ray and single particle EM techniques.

Probing the stereoselective interaction of ofloxacin enantiomers with corresponding monoclonal antibodies by multiple spectrometry.

Although stereoselective antibody has immense potential in chiral compounds detection and separation, the interaction traits between stereoselective antibody and the corresponding antigenic enantiomers are not yet fully exploited. In this study, the stereospecific interactions between ofloxacin isomers and corresponding monoclonal antibodies (McAb-WR1 and McAb-MS1) were investigated using time-resolved fluorescence, steady-state fluorescence, and circular dichroism (CD) spectroscopic methods. The chiral recognition discrepancies of antibodies with ofloxacin isomers were reflected through binding constant, number of binding sites, driving forces and conformational changes.

Analytical Application of Lectins.

This review is devoted to the analytical application of carbohydrate-binding proteins called lectins. The nature of lectins and the regularities of their specificity with respect to simple sugars and complex carbohydrate-containing biomolecules are discussed. The main areas of the modern analytical application of lectins are described.

Theoretical and Experimental Comparison of Different Formats of Immunochromatographic Serodiagnostics.

In this study, a comparative theoretical and experimental analysis of two immuno-chromatographic serodiagnostics schemes, which differ in the immobilization of immunoreagents and the order of the formation of immune complexes, is performed. Based on the theoretical models, the assays are characterized to determine which scheme has a higher quantity of the detected complex and thus ensures the sensitivity of the analysis. The results show that for the effective detection of low-affinity antibodies, the scheme involving the immobilization of the antigen on gold nanoparticles and the antibody-binding protein on the test strip was more sensitive than the predominantly used scheme, which inverts the immunoreagents' locations.

Functional role of the core gap in the middle part of tropomyosin.

Tropomyosin (Tpm) is an α-helical coiled-coil actin-binding protein playing an essential role in the regulation of muscle contraction. The middle part of the Tpm molecule has some specific features, such as the presence of noncanonical residues as well as a substantial gap at the interhelical interface, which are believed to destabilize a coiled-coil and impart structural flexibility to this part of the molecule. To study how the gap affects structural and functional properties of α-striated Tpm (the Tpm1.

Binding of thioflavin T by albumins: An underestimated role of protein oligomeric heterogeneity.

Amyloid fibrils formation is the well-known hallmark of various neurodegenerative diseases. Thioflavin T (ThT)-based fluorescence assays are widely used to detect and characterize fibrils, however, if performed in bioliquids, the analysis can be biased due to the presence of other, especially abundant, proteins. Particularly, it is known that albumin may bind ThT, although the binding mechanism remains debatable.

Association of Multiple Phosphorylated Proteins with the 14-3-3 Regulatory Hubs: Problems and Perspectives.

14-3-3 proteins are well-known universal regulators binding a vast number of partners by recognizing their phosphorylated motifs, typically located within the intrinsically disordered regions. The abundance of such phosphomotifs ensures the involvement of 14-3-3 proteins in sophisticated protein-protein interaction networks that govern vital cellular processes. Thousands of 14-3-3 partners have been either experimentally identified or predicted, but the spatiotemporal hierarchy of the processes based on 14-3-3 interactions is not clearly understood.

The photocycle of orange carotenoid protein conceals distinct intermediates and asynchronous changes in the carotenoid and protein components.

The 35-kDa Orange Carotenoid Protein (OCP) is responsible for photoprotection in cyanobacteria. It acts as a light intensity sensor and efficient quencher of phycobilisome excitation. Photoactivation triggers large-scale conformational rearrangements to convert OCP from the orange OCP state to the red active signaling state, OCP, as demonstrated by various structural methods.

Transient interaction between the N-terminal extension of the essential light chain-1 and motor domain of the myosin head during the ATPase cycle.

The molecular mechanism of muscle contraction is based on the ATP-dependent cyclic interaction of myosin heads with actin filaments. Myosin head (myosin subfragment-1, S1) consists of two major domains, the motor domain responsible for ATP hydrolysis and actin binding, and the regulatory domain stabilized by light chains. Essential light chain-1 (LC1) is of particular interest since it comprises a unique N-terminal extension (NTE) which can bind to actin thus forming an additional actin-binding site on the myosin head and modulating its motor activity.

Benzoylphenyl thiocyanates are new, effective inhibitors of the mycobacterial resuscitation promoting factor B protein.

Background: Resuscitation promoting factors (Rpfs) are the proteins involved in the process of reactivation of the dormant cells of mycobacteria. Recently a new class of nitrophenylthiocyanates (NPTs), capable of inhibiting the biological and enzymatic activities of Rpfs has been discovered. In the current study the inhibitory properties of the compounds containing both nitro and thiocyanate groups alongside with the compounds with the modified number and different spatial location of the substituents are compared.