Interferon-Inducible Myxovirus Resistance Proteins: Potential Biomarkers for Differentiating Viral from Bacterial Infections.

Background: In 2015, the 68th World Health Assembly declared that effective, rapid, low-cost diagnostic tools were needed for guiding optimal use of antibiotics in medicine. This review is devoted to interferon-inducible myxovirus resistance proteins as potential biomarkers for differentiating viral from bacterial infections.

Content: After viral infection, a branch of the interferon (IFN)-induced molecular reactions is triggered by the binding of IFNs with their receptors, a process leading to the activation of and , which produce antiviral Mx proteins (MxA and MxB).

Binding of cholera toxin B subunit to intestinal epithelial cells.

We have prepared I-labeled cholera toxin B subunit (I-labeled CT-B, a specific activity of 98Ci/mmol) and found that it binds to rat IEC-6 and human Caco-2 intestinal epithelial cells with high affinity (K 3.6 and 3.7nM, respectively).

Human myeloma IgG4 reveals relatively rigid asymmetric Y-like structure with different conformational stability of C2 domains.

Human IgG4 (hIgG4) has weak pro-inflammatory activity. The structural basis for this is still unclear. Here a 3D model of myeloma hIgG4 was created at ∼3nm resolution using electron microscopy (EM) with negative staining and single-particle 3D reconstruction.

Interaction of cholera toxin B subunit with T and B lymphocytes.

We have prepared I-labeled cholera toxin B subunit (I-labeled CT-B, a specific activity of 98Ci/mmol) and found that its binding to T and B lymphocytes from the blood of healthy donors was high-affinity (K 2.8 and 3.0nM, respectively).

Resolving the energy paradox of chaperone/usher-mediated fibre assembly.

Periplasmic chaperone/usher machineries are used for assembly of filamentous adhesion organelles of Gram-negative pathogens in a process that has been suggested to be driven by folding energy. Structures of mutant chaperone-subunit complexes revealed a final folding transition (condensation of the subunit hydrophobic core) on the release of organelle subunit from the chaperone-subunit pre-assembly complex and incorporation into the final fibre structure. However, in view of the large interface between chaperone and subunit in the pre-assembly complex and the reported stability of this complex, it is difficult to understand how final folding could release sufficient energy to drive assembly.

Folding of the human immunoglobulin G3 Kus core hinge into the thirteenth globular domain.

Earlier, the electron microscopy and hydrodynamic studies revealed the transformation of the globule-like form of the human (h) IgG3 Kus hinge into a rod-like shape under non-denaturing perturbations [Eur. J. Biochem.

Core hinge of human immunoglobulin G3 as a system of four independent co-operative blocks.

On the heat absorption curves of human immunoglobulin G3 (hIgG3) Kuc melting the scanning calorimetry method reveals a high-temperature (high-T(m)) peak of high intensity that is absent at the curves of other hIgG subclasses and IgG of other species. An analogous peak is observed also at the curves of melting of hIgG3 fragments containing the hinge segments. The high-T(m) peak is accompanied by characteristic changes in circular dichroism (CD) spectra at 220-230 nm.

Long-term metastable conformation of human Fcgamma subunit.

It was found that the human (hu) myeloma IgG1 Ser, its Fcgamma fragment and the chimeric mouse-human monoclonal antibody (chim-mAb), containing the constant part of hu-gamma1-chain, can exist in a long-term metastable conformational state. This state arises as a result of short incubation of IgG molecules and their Fcgamma fragments at pH<2.8 and the consequent rapid neutralisation to pH 7.

Synthetic peptide SLTCLVKGFY competes with beta-endorphin for naloxone-insensitive binding sites on rat brain membranes.

The synthetic decapeptide Ser-Leu-Thr-Cys-Leu-Val-Lys-Gly-Phe-Tyr (termed immunorphin) corresponding to the sequence 364-373 of the CH3 domain of human immunoglobulin G heavy chain and its synthetic fragment VKGFY were found to compete with 125I-labeled beta-endorphin for high-affinity naloxone-insensitive binding sites on membranes isolated from the rat brain cortex (K(i)=1.18+/-0.09 and 1.