Selection of cyclic peptide aptamers to HCV IRES RNA using mRNA display

The Blockchain Integrated Automatic Experiment Platform (BiaeP)

Given that robots are being utilized extensively in chemical synthesis research, the potential applications of robots remain to be explored. Along with the remarkable progress of experimental science, circumstances have occurred in which publications were castigated because of irreproducibility, either because of rigorous experimental conditions or because of initial data forgery. Some credit-assignment issues and plagiarism cases also attracted intense attention throughout the community. As a possible solution to authenticity and originality problems, we herein propose a blockchain integrated automatic experiment platform, BiaeP, which attempts to provide solutions for those kinds of problems. As a result of the integration with blockchain, its data irreversibility secures the authenticity and the timestamp helps prove the originality. Two trial experiments are included as examples. We believe the architecture of BiaeP could be widely applicable for future development of scientific research in experimental subjects, such as chemistry, materials science, biology, and so forth.

Screening of the candidate inhibitory peptides of subtilisin by in vitro RNA display technique

The application of inhibitors facilitates the stable preservation of enzyme in liquid detergent by mitigating the proteolytic activity of subtilisin. The conventionally used subtilisin inhibitors such as boric acid pose a threat to the environment and human health. Thus, the formulation of novel subtilisin inhibitors demands immediate attention. In the current study, we have screened the peptide inhibitors for subtilisin by employing the in vitro mRNA display technique. It is a sensitive screening technique with a high library capacity. The affinity screening was performed between the biotin-modified subtilisin immobilized on the streptavidin magnetic beads and the cDNA-mRNA-peptide fusion molecular library acquired from the in vitro translation and reverse transcription. The candidate peptides with high affinity were obtained after multiple rounds of screening. Furthermore, the inhibitory effect was evaluated, showing that some candidate peptides had inhibitory effects, but the isothermal titration calorimetry and time dependent experiments ultimately proved that these candidate peptides were not stable inhibitors. However, the in vitro mRNA display method explored in this study can be used as a preliminary screening method to provide candidate peptides for the screening of subtilisin inhibitors.

Antiviral Peptides: Identification and Validation

Despite rapid advances in the human healthcare, the infection caused by certain viruses results in high morbidity and mortality accentuate the importance for development of new antivirals. The existing antiviral drugs are limited, due to their inadequate response, increased rate of resistance and several adverse side effects. Therefore, one of the newly emerging field “peptide-based therapeutics” against viruses is being explored and seems promising. Over the last few years, a lot of scientific effort has been made for the identification of novel and potential peptide-based therapeutics using various advanced technologies. Consequently, there are more than 60 approved peptide drugs available for sale in the market of United States, Europe, Japan, and some Asian countries. Moreover, the number of peptide drugs undergoing the clinical trials is rising gradually year by year. The peptide-based antiviral therapeutics have been approved for the Human immunodeficiency virus (HIV), Influenza virus and Hepatitis virus (B and C). This review enlightens the various peptide sources and the different approaches that have contributed to the search of potential antiviral peptides. These include computational approaches, natural and biological sources (library based high throughput screening) for the identification of lead peptide molecules against their target. Further the applications of few advanced techniques based on combinatorial chemistry and molecular biology have been illustrated to measure the binding parameters such as affinity and kinetics of the screened interacting partners. The employment of these advanced techniques can contribute to investigate antiviral peptide therapeutics for emerging infections.

New Molecular Insights into the Inhibition of Dipeptidyl Peptidase-4 by Natural Cyclic Peptide Oxytocin

Protease inhibition has led to treating many diseases and has been successful in producing many commercial drugs by pharmaceutical companies. Among many proteases, serine protease has been attractive in treating metabolic disorder diabetes mellitus (DM). Gliptins have been proven to inhibit dipeptidyl peptidase-4 (DPP4), a serine protease, and are an emerging therapeutic drug target to reduce blood glucose levels, but until now there is no natural cyclic peptide proven to inhibit serine protease DPP4. This study demonstrates the potential mechanism of natural cyclic peptide oxytocin (OXT) as a DPP4 inhibitor. To achieve this, initially, activity atlas and field-based models of DPP4 inhibitors were utilized to predict the possible features of positive and negative electrostatic, hydrophobic, and activity shapes of DPP4 inhibition. Oxytocin binding mode, flexibility, and interacting residues were studied using molecular docking simulations studies. 3D-RISM calculations studies revealed that the stability of water molecules at the binding site are favorable. Finally, an experimental study using fluorescence assay revealed OXT inhibits DPP4 in a concentration-dependent manner in a significant way (p < 0.05) and possess IC50 of 110.7 nM. These new findings significantly expand the pharmaceutical application of cyclic peptides, and in specific OXT, and implicate further optimization of OXT inhibition capacity to understand the effect of DPP4 inhibition. This work highlights the development of natural cyclic peptides as future therapeutic peptides to reduce glucose levels and treat diabetes mellitus.

Lamarck and Panspermia - On the Efficient Spread of Living Systems Throughout the Cosmos

We review the main lines of evidence (molecular, cellular and whole organism) published since the 1970s demonstrating Lamarckian Inheritance in animals, plants and microorganisms viz. the transgenerational inheritance of environmentally-induced acquired characteristics. The studies in animals demonstrate the genetic permeability of the soma-germline Weismann Barrier. The widespread nature of environmentally-directed inheritance phenomena reviewed here contradicts a key pillar of neo-Darwinism which affirms the rigidity of the Weismann Barrier. These developments suggest that neo-Darwinian evolutionary theory is in need of significant revision. We argue that Lamarckian inheritance strategies involving environmentally-induced rapid directional genetic adaptations make biological sense in the context of cosmic Panspermia allowing the efficient spread of living systems and genetic innovation throughout the Universe. The Hoyle-Wickramasinghe Panspermia paradigm also developed since the 1970s, unlike strictly geocentric neo-Darwinism provides a cogent biological rationale for the actual widespread existence of Lamarckian modes of inheritance - it provides its raison d'être. Under a terrestrially confined neo-Darwinian viewpoint such an association may have been thought spurious in the past. Our aim is to outline the conceptual links between rapid Lamarckian-based evolutionary hypermutation processes dependent on reverse transcription-coupled mechanisms among others and the effective cosmic spread of living systems. For example, a viable, or cryo-preserved, living system travelling through space in a protective matrix will need of necessity to rapidly adapt and proliferate on landing in a new cosmic niche. Lamarckian mechanisms thus come to the fore and supersede the slow (blind and random) genetic processes expected under a traditional neo-Darwinian evolutionary paradigm.

Charging of tRNAs using ribozymes and selection of cyclic peptides containing thioethers

In vitro selection methods represent a powerful approach toward identifying high-affinity peptide ligands from highly diverse peptide libraries against a desired target. We herein describe a method for the display and selection of cyclic thioether peptide libraries. Reprogramming the initiation event from fMet to an N-chloroacetyl-amino acid by utilizing flexizyme to rapidly and efficiently prepare the aa-tRNA can be effectively used to initiate translation, upon which the thiol group of an inserted cysteine at the C terminus of the designed library spontaneously reacts to yield a nonreducible cyclic thioether peptide readily compatible with any in vitro display methods. Thus, cyclic peptides already in a nonreducible stable form can be selected directly against the target of interest.

Strategies for the design of RNA-binding small molecules

Bacterial ribosomal RNA is the target of clinically important antibiotics, while biologically important RNAs in viral and eukaryotic genomes present a range of potential drug targets. The physicochemical properties of RNA present difficulties for medicinal chemistry, particularly when oral availability is needed. Peptidic ligands and analysis of their RNA-binding properties are providing insight into RNA recognition. RNA-binding ligands include far more chemical classes than just aminoglycosides. Chemical functionalities from known RNA-binding small molecules are being exploited in fragment- and ligand-based projects. While targeting of RNA for drug design is very challenging, continuing advances in our understanding of the principles of RNA–ligand interaction will be necessary to realize the full potential of this class of targets.

Phage-encoded combinatorial chemical libraries based on bicyclic peptides

Here we describe a phage strategy for the selection of ligands based on bicyclic or linear peptides attached covalently to an organic core. We designed peptide repertoires with three reactive cysteine residues, each spaced apart by several random amino acid residues, and we fused the repertoires to the phage gene-3-protein. Conjugation with tris-(bromomethyl)benzene via the reactive cysteines generated repertoires of peptide conjugates with two peptide loops anchored to a mesitylene core. Iterative affinity selections yielded several enzyme inhibitors; after further mutagenesis and selection, we were able to chemically synthesize a lead inhibitor (PK15; Ki =1.5 nM) specific to human plasma kallikrein that efficiently interrupted the intrinsic coagulation pathway in human plasma tested ex vivo. This approach offers a powerful means of generating and selecting bicyclic macrocycles (or if cleaved, linear derivatives thereof) as ligands poised at the interface of small-molecule drugs and biologics.