Biomacromolecular Journal
Volume:5 Issue: 2, Autumn 2019

L-Arginine (Arg or R) is a non-toxigenic, metabolically versatile and conditionally essential amino acid. Single-pot synthesis of Arg modified magnetic nanoparticles (RMNPs) was achieved using magnetite nanoparticles (MNPs) and binary function of Arg as a functional group and an alkali precipitator. This modification is supposed to offer several advantages to the MNPs from a bio-application viewpoint. Here, the influence of RMNPs in the structure and function of the model protein hen egg white lysozyme (HEWL) is reported. After synthesis of RMNPs, VSM, XRD, FT-IR, Zetasizer, TEM, and SEM were used to characterize the nanoparticles. The impact of RMNPs was investigated on lysozyme structure and activity during storage and in the processes of denaturation and refolding by dilution or dialysis using fluorescence, circular dichroism (CD) and UV/Vis spectroscopies. RMNPs revealed structural ordering or disordering effects on lysozyme in a RMNP:HEWL ratio dependent manner. Accordingly, a concentration ratio of threshold (CRT) was determined at 0.296. At ratios lower than the CRT the protein gained more ordered structure with increased helicity. Inversely, HEWL was increasingly unfolded and helicity was decreased at ratios higher than the CRT, rendering the protein more disordered after interaction with RMNPs. At RMNPs:HEWL concentration ratios above and even below the CRT, 6 M urea had a further disordering effect. Nevertheless, significant improvements were observed in the refolding of the protein due to dilution or dialysis, by courtesy of the RMNPs. The presented data helps to expand the thriving applications of RMNPs in biotechnology and biomedicine.

Epigenetic changes such as histone acetylation changes affecting genes play an important role in the development of various human cancers. HDAC inhibitors are now approved by the FDA for the treatment of cancer malignancies as well as clinical trials for tumors. Histone deacetylases play a role in the onset and progression of many cancers through effects on cell cycle, epithelial differentiation and apoptosis. We examined the antiproliferative effects of valproate with a combination of nicotinamide in human glioblastoma U87 cell line. The MTT assay showed that valproate at 0.5 mM, when used alone weakly, suppressed proliferation of cells (39%±3.05) and combination treatment of valproate + nicotinamide strongly suppressed cell proliferation (60%±3.5). Flow cytometric analysis showed that in the treatment of cells when the combination of valproate and nicotinamide was used, it showed more inhibitory effects on cell viability than when valproate alone was used. Also, western blot analyses have done to study the acetyl-histone H3 levels, and quantitative Real time PCR were performed on expression of p21 gene in U87 cell line. The combination treatment of valproate + nicotinamide enhanced the expression of p21 gene. The biological response of the cell line correlated with the increase of histone H3 acetylation after nicotinamide and valproate application. The findings indicate that co-administration of valproate and nicotinamide can have inhibitory effects on the growth and proliferation of human glioblastoma U-87 cells and may be a suitable option for new treatments for brain tumors. Key words: U87 cell, HDAC, HAT, Valproate, Nicotinamide

Nano-drug delivery has attracted great attention in improving the efficacy of anticancer drugs. This study described the preparation of a nanosize carrier based on protein and reduced graphene oxide (rGO) for sustained release and the enhancement of the treatment efficacy of carboplatin in breast cancer cell lines. Moreover, the characterization of bovine serum albumin nanoparticles (BSANP)-coated rGO nanosheets (rGO-BSANP) was performed by FTIR, DLS and SEM techniques. The results demonstrated that BSANP and rGO bond to each other with an average size of 753.1 nm and a surface charge of -16.0 mV. Entrapment efficiency and drug loading of rGO-BSANP in three different ratios (1:1, 1:5 and 1:10) were determined. In vitro carboplatin release from rGO, BSANP and different ratios of rGO-BSANP at 300 min showed that the rGO-BSANP nanocarrier with 1:1 ratio was an appropriate system. Furthermore, the cytotoxicity of carboplatin, rGO-BSANP and carboplatin loaded rGO-BSANP (car@rGO-BSANP) was evaluated using the MTT assay, on breast cancer cell lines, MCF7. Results showed that the presence of nanocarrier caused IC50 of carboplatin significantly decreased. Hence, the designed nanocarrier helps sustained release and a lower concentration of carboplatin for cancer treatment.

Abstract Diuron is being used as an herbicide in agricultural crops and non-crops areas such as roads, garden paths, and railway lines. According to clinical studies, it is slightly toxic to mammals, birds and human health. In this study, the intermolecular interaction of Diuron and human hemoglobin was investigated using various spectroscopic methods. The UV-visible and fluorescence results showed that the Diuron binds to Hb. According to the linear S-V plot, dynamic enhancement constant reduced with rising of temperature. Diuron formed a complex with HHb by static mechanism of enhancement and changed the conformation of Hb. The thermodynamic result suggested that the binding reaction was spontaneous and exothermic. Also, the result of synchronous fluorescence, heme degradation, thermal denaturation, aggregation and determination of surface hydrophobicity indicated that the Diuron could induce the conformational alteration, unfolding and heme degradation of Hb. bioanformatics study used for deciphering the binding location of a ligand to a biomicromolecules. According to molecular docking results the Diuron binds near the hydrophobic pocket of Hb which hydrophobic residue was located in this region.

Antioxidants are of great importance because they can protect the body from oxidation agents. Reactive oxygen species (ROS) are constantly producing as a result of metabolic processes. However, environmental factors such as methyl tert-butyl ether (MTBE) can enhance oxidation stress. MTBE is a widely used fuel oxygenation liquid that has been shown to cause potential cancer. The use of antioxidants may help to reduce the oxidation condition caused by MTBE. Selenium is an essential element with antioxidant property. In this study, the interaction between Cyt C and MTBE has been investigated in the absence and presence of Se. Molecular level examinations are extremely important to investigate the structural change of proteins by MTBE. In this research, molecular behaviour of Cyt c as an important model of protein, in the presence and absence of MTBE and Se is detected by biophysical methods such as UV-vis, fluorescence and FTIR spectroscopy, chemiluminescence and molecular docking. The results showed that MTBE is able to alter Cyt c tertiary structure by ROS production with no change in secondary structure and Se could not protect the protein from structural perturbation. Molecular docking was also confirmed by the prominent interaction of Cyt c with MTBE and Se at a different site. Then Se can cause the structural change of Cyt c.

Gold nanoparticles are promising materials for biomedical applications because of the attractive optical properties such as the absorption and scattering of light at resonant wavelength. Due to the fruitful applications of gold nanoparticles (GNPs), they are appropriate for a variety of biological studies. One of the most important applications of nanoparticles is protein carriers, in which transport of therapeutically relevant protein is done to in vivo or in vitro targets. Protein folding and properties of probable intermediates during the folding of proteins had been investigated in several studies. The molten globule state, a main intermediate of protein folding, has native-like secondary but perturbation of tertiary structure. Consequently, the influence of gold nanoparticles concentration on a model protein was studied by far- and near-UV circular dichroism (CD), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), intrinsic fluorescence emission spectroscopy and 8-Anilino-1-naphthalenesulfonic acid binding. The results indicated that the interactions between gold nanoparticles and lysozyme lead to the formation of molten globule-like state.

Bacterial cell-surface proteins (S-layer proteins) have an extremely repetitive surface structure well suited as a biotemplate to fabricate metallic/semiconducting nanostructures; an issue of high importance to the electronic industry. The surface layer proteins of Deinococcus radiodurans R1 (HPI) is an attractive S-layer for arraying nanoparticles. It illustrates hexagonal symmetry which is composed of a hexameric protein core unit with a middle hole. In this study, hexagonally structure of HPI protein was confirmed by AFM. Transmission electron microscopy and Fourier transform analysis revealed the formation of hexagonally ordered arrays of 4.5nm citrate-capped Au nanoparticles. Also, the influence of stability and dispersity of gold nanoparticles has been investigated on the fabrication of ordered arrays by nanoparticle’s zeta potential. The results reflect the effect of nanoparticles’ zeta potential value on the creation of their ordered arrays through HPI layer, which could be useful in using these ordered nanoarrays for fabricating bio-sensors and some electronic devices.

This study aimed to investigate the interaction between 5-(2-hydroxy-2-oxo-2,3-dihydro-1H-indol-3-yl)-1,3thiazolidine-2,4-dione (oxindole A) and DNA with and without ultrasound treatment. Absorption studies have indicated that oxindole A could bind to CT-DNA with the binding constant of 30,000 and 26,666 M-1 with and without ultrasound treatment, respectively. In the competitive fluorescence method, the displacement of 4′,6-diamidino-2-phenylindole (DAPI) as a probe bound to the groove, from the DNA groove occurred by oxindole A. Using the Stern-Volmer plot, quenching constant was calculated to be 1,411 and 2,753 M-1 with and without ultrasound, respectively. Viscometric experiments have confirmed the groove binding of oxindole A to the DNA, which is consistent with the molecular dynamic simulation. The analysis of Pi, as a measure of affinity for ligand binding, has also revealed that the DA3, DG4, DC5, DT7, DC8, and DG9 of DNA have the highest affinity toward oxindole A. In addition, the results of the cell viability assay of the DU145 cell line have demonstrated that oxindole A has cytotoxic effects.