Characterizing α‑Helical Peptide Aggregation on Supported Lipid Membranes Using Microcantilevers

We report the use of lipid membrane-coated microcantilevers to probe the interactions between phospholipid membranes and membrane-active peptides. This sensing method integrates two well-developed techniques: solid-supported lipid bilayers (SLBs) and microcantilever sensors. SLBs are prepared on the silicon dioxide surface of the microcantilevers using a vesicle fusion method. As molecules adsorb onto the surface of the microcantilever, the microcantilever bends due to the induced compressive or tensile stresses, which result from the surface free energy change. Real-time surface stress changes in the SLB due to interactions with small molecules can be detected by monitoring the deflection of the microcantilever. We investigate the mechanism for the interaction between SLBs and PEP1, a synthetic amphipathic peptide resembling a segment of the nonstructural protein (NS5A) of the hepatitis C virus. Initially, the PEP1 peptides adsorb onto the lipid membranes, and then at a critical concentration, the peptides begin to aggregate and form pores; finally, the peptides destabilize and induce solubilization of the supported membranes. The membrane-coated microcantilever sensor is capable of characterizing the kinetics and dynamics of this process with great sensitivity

Computational Study Exploring the Interaction Mechanism of Benzimidazole Derivatives as Potent Cattle Bovine Viral Diarrhea Virus Inhibitors

Bovine viral diarrhea virus (BVDV) infections are prevailing in cattle populations on a worldwide scale. The BVDV RNA-dependent RNA polymerase (RdRp), as a promising target for new anti-BVDV drug development, has attracted increasing attention. To explore the interaction mechanism of 65 benzimidazole scaffold-based derivatives as BVDV inhibitors, presently, a computational study was performed based on a combination of 3D-QSAR, molecular docking, and molecular dynamics (MD) simulations. The resultant optimum CoMFA and CoMSIA models present proper reliabilities and strong predictive abilities (with <i>Q</i>² = 0. 64, <i>R</i>²_ncv = 0.93, <i>R</i>²_pred = 0.80 and <i>Q</i>² = 0. 65, <i>R</i>²_ncv = 0.98, <i>R</i>²_pred = 0.86, respectively). In addition, there was good concordance between these models, molecular docking, and MD results. Moreover, the MM-PBSA energy analysis reveals that the major driving force for ligand binding is the polar solvation contribution term. Hopefully, these models and the obtained findings could offer better understanding of the interaction mechanism of BVDV inhibitors as well as benefit the new discovery of more potent BVDV inhibitors

Oriented Enzyme Immobilization at the Oil/Water Interface Enhances Catalytic Activity and Recyclability in a Pickering Emulsion

Enzyme-loaded water-in-oil Pickering emulsion is a promising system for biphasic catalytic reactions. In this paper, we report on oriented enzyme immobilization at the oil/water interface in a Pickering emulsion, in which CHO-Janus silica nanoparticles (CHO-JNPs) are utilized as a stabilizer of the emulsion and support for the enzyme to enhance both catalytic activity and recyclability. The catalytic performance of this immobilized enzyme (lipase from Candida sp.) was evaluated by esterification of hexanoic acid and 1-hexanol in a water/heptane biphasic medium. The results show that the specific catalytic activity of the immobilized enzyme (33.2 U mL^–1) was 6.5 and 1.4 times higher than that of free enzyme (5.1 U mL^–1) and encapsulated enzyme in the liquid core (23.3 U mL^–1), respectively. Moreover, the immobilized enzyme demonstrated good stability and recyclability, retaining 75% of its activity after 9 cycles. We expect that oriented enzyme immobilization at the oil/water interface will be an important strategy for enhancing catalytic performance in Pickering emulsions

A Methodology for Cancer Therapeutics by Systems Pharmacology-Based Analysis: A Case Study on Breast Cancer-Related Traditional Chinese Medicines

<div><p>Breast cancer is the most common carcinoma in women. Comprehensive therapy on breast cancer including surgical operation, chemotherapy, radiotherapy, endocrinotherapy, etc. could help, but still has serious side effect and resistance against anticancer drugs. Complementary and alternative medicine (CAM) may avoid these problems, in which traditional Chinese medicine (TCM) has been highlighted. In this section, to analyze the mechanism through which TCM act on breast cancer, we have built a virtual model consisting of the construction of database, oral bioavailability prediction, drug-likeness evaluation, target prediction, network construction. The 20 commonly employed herbs for the treatment of breast cancer were used as a database to carry out research. As a result, 150 ingredient compounds were screened out as active molecules for the herbs, with 33 target proteins predicted. Our analysis indicates that these herbs 1) takes a ‘Jun-Chen-Zuo-Shi” as rule of prescription, 2) which function mainly through perturbing three pathways involving the epidermal growth factor receptor, estrogen receptor, and inflammatory pathways, to 3) display the breast cancer-related anti-estrogen, anti-inflammatory, regulation of cell metabolism and proliferation activities. To sum it up, by providing a novel <i>in silico</i> strategy for investigation of the botanical drugs, this work may be of some help for understanding the action mechanisms of herbal medicines and for discovery of new drugs from plants.</p></div

Thioether-Bonded Fluorescent Probes for Deciphering Thiol-Mediated Exchange Reactions on the Cell Surface

Study on the processes of the thiol-mediated disulfide exchange reactions on the cell surface is not only important to our understanding of extracellular natural bioreduction processes but to the development of novel strategies for the intracellular delivery of synthetic bioactive molecules. However, disulfide-bonded probes have their intrinsic inferiority in exploring the detailed exchange pathway because of the bidirectional reactivity of disulfide bonds toward reactive thiols. In this work, we developed thioether-bonded fluorescent probes that enable us to explore thiol-mediated thioether (and disulfide) exchange reactions on the cell surface through fluorescence recovery and/or cell imaging. We demonstrated that our thioether-bonded probes can be efficiently cleaved through thiol-thioether exchanges with exofacial protein thiols and/or glutathione (GSH) efflux. The exchanges mainly take place on the cell surface, and GSH efflux-mediated exchange reactions can take place without the requirement of pre-exchanges of the probes with cell surface-associated protein thiols. On the basis of our founder methodology, for the first time we demonstrated the interplay of exofacial protein thiols and GSH efflux on the cleavage of external thioether-bonded compounds. Moreover, given that an understanding of the process of GSH efflux and the mechanism on which it relies is crucial to our understanding of the cellular redox homeostasis and the mechanism of multidrug resistance, we expect that our thioether-bonded probes and strategies would greatly benefit the fundamental study of GSH efflux in living cells

150 bioactive compounds of the 20 herbs with their predicted OB and DL values.

<p>150 bioactive compounds of the 20 herbs with their predicted OB and DL values.</p

The profile distributions of eight important molecular properties for DrugBank drugs and herbal compounds.

<p>The profile distributions of eight important molecular properties for DrugBank drugs and herbal compounds.</p

The global view of C-T network for the 20 breast cancer-related herbs.

<p>(A) 32 bioactive compounds (orange squares) from <i>Radix Salviae</i> applied as monarch herbal medicine play principal roles in therapeutic effect. 41 bioactive compounds (green squares) from 7 herbs represent those minister herbal medicine which increase the effects of <i>Radix Salviae</i>. 57 bioactive compounds (magenta and blue squares) from 12 herbs serve as assistant and messenger drugs, respectively. The yellow circles represent the target proteins of the active compounds. (B) The combination principle of Jun-Chen-Zuo-Shi.</p

Gene Ontology (GO) analysis of therapy target genes.

<p>The y-axis shows significantly enriched ‘Biological Process ‘ (BP) categories in GO relative to the target genes, and the x-axis depicts the enrichment scores of these terms (<i>p</i>-value≤0.05).</p

The T-P network.

<p>A link is created between a target and a pathway if the pathway is lighted at the target, where blue, green and red nodes represent compounds, targets and pathways, respectively. The information of pathways is obtained by mapping the target proteins to the KEGG pathway database.</p