The Contribution of Hydrophobic Interactions to Conformational Changes of Inward/Outward Transmembrane Transport Proteins

Effect of abamectin on osmoregulation in red swamp crayfish (Procambarus clarkii)

As a widely used pesticide, abamectin could be a threat to nontarget organisms. In this study, the toxic mechanism of abamectin on osmoregulation in Procambarus clarkii was explored for the first time. The results of this study showed that with increasing abamectin concentration, the membrane structures of gill filaments were damaged, with changes in ATPase activities, transporter contents, biogenic amine contents, and gene expression levels. The results of this study indicated that at 0.2 mg/L abamectin, ion diffusion could maintain osmoregulation. At 0.4 mg/L abamectin, passive transport was inhibited due to damage to the membrane structures of gill filaments, and active transport needed to be enhanced for osmoregulation. At 0.6 mg/L abamectin, the membrane structures of gill filaments were seriously damaged, and the expression level of osmoregulation-related genes decreased, but the organisms were still mobilizing various transporters, ATPases, and biogenic amines to address abamectin stress. This study provided a theoretical basis for further study of the effects of contaminations in aquatic environment on the health of crustaceans.

Transmembrane proteins-Different anchoring systems

Transmembrane proteins are active in amphipathic environments. To stabilize the protein in such surrounding the exposure of hydrophobic residues on the protein surface is required. Transmembrane proteins are responsible for the transport of various molecules. Therefore, they often represent structures in the form of channels. This analysis focused on the stability and local flexibility of transmembrane proteins, particularly those related to their biological activity. Different forms of anchorage were identified using the fuzzy oil-drop model (FOD) and its modified form, FOD-M. The mainly helical as well as β-barrel structural forms are compared with respect to the mechanism of stabilization in the cell membrane. The different anchoring system was found to stabilize protein molecules with possible local fluctuation.

Lifting the veils on transmembrane proteins: Potential anticancer targets

Cancer, as a prevalent cause of mortality, poses a substantial global health burden and hinders efforts to enhance life expectancy. Nevertheless, the prognosis of patients with malignant tumors remains discouraging, owing to the lack of specific diagnostic and therapeutic targets. Therefore, the development of early diagnostic indicators and novel therapeutic drugs for the prevention and treatment of cancer is essential. Transmembrane proteins (TMEMs) are a class of proteins that can span the phospholipid bilayer and are stably anchored. They are associated with fibrotic diseases, neurodegenerative diseases, autoimmune diseases, developmental disorders, and cancer. It has been found that the expression levels of TMEMs were elevated or reduced in cancer cells, exerting pro/anticancer effects. These aberrant expression levels have also been linked to the prognostic and clinicopathological features of diverse tumors. In this review, the structures, functions, and roles of TMEMs in cancer were discussed, and the scientific perspectives were described. This review also explored the potential of TMEMs as tumor drug candidates from the perspective of targeted therapies, and the challenges that need to be overcome in a wide range of preclinical and clinical anticancer research were summarized.

New insights on the catalytic center of proteins from peptidylprolyl isomerase group based on the FOD-M model

Generating the structure of the hydrophobic core is based on the orientation of hydrophobic residues towards the central part of the protein molecule with the simultaneous exposure of polar residues. Such a course of the protein folding process takes place with the active participation of the polar water environment. While the self-assembly process leading to the formation of micelles concerns freely moving bi-polar molecules, bipolar amino acids in polypeptide chain have limited mobility due to the covalent bonds. Therefore, proteins form a more or less perfect micelle-like structure. The criterion is the hydrophobicity distribution, which to a greater or lesser extent reproduces the distribution expressed by the 3D Gaussian function on the protein body. The vast majority of proteins must ensure solubility, so a certain part of it-as it is expected-should reproduce the structuring of micelles. The biological activity of proteins is encoded in the part that does not reproduce the micelle-like system. The location and quantitative assessment of the contribution of orderliness to disorder is of critical importance for the determination of biological activity. The form of maladjustment to the 3D Gauss function may be varied-hence the obtained high diversity of specific interactions with strictly defined molecules: ligands or substrates. The correctness of this interpretation was verified on the basis of the group of enzymes Peptidylprolyl isomerase-E.C.5.2.1.8. In proteins representing this class of enzymes, zones responsible for solubility-micelle-like hydrophobicity system-the location and specificity of the incompatible part in which the specific activity of the enzyme is located and coded were identified. The present study showed that the enzymes of the discussed group show two different schemes of the structure of catalytic center (taking into account the status as defined by the fuzzy oil drop model).