Direct bioelectrocatalysis at the interfaces by genetically engineered dehydrogenase

This is the published version.There is an emerging interest in developing bio-functionalisation routes serving as platforms for assembling diverse enzymes onto material surfaces. Specifically, the fabrication of next-generation, laboratory-on-a-chip-based sensing and energy harvesting systems requires controlled orientation and organisation of the proteins at the inorganic interfaces. Herein, the authors take the initial steps towards designing multifunctional, enzyme-based platforms by genetically integrating the engineered materialselective peptide tags for tethering redox enzymes onto electrode surfaces. The authors engineered a fusion protein that genetically conjugates gold-binding peptide to formate dehydrogenase derived from Candida methylica. The expressed proteins were tested for both enzyme activity and self-directed gold-surface functionalisation ability. Their findings demonstrate the successful self-immobilisation of the engineered enzyme onto different gold electrodes while retaining the catalytic activity. Building on the functionalisation by the peptides, a fusion enzyme-integrated circuit-based biosensor system was designed. The catalytic conversion of the formate by the engineered dehydrogenase was successfully monitored on the electrode surface at subsequent intervals. The engineered peptide-mediated self-integrated electrode systems can be extended to develop a wide range of biosensing and energy-harvesting platforms using different combinations of materials and biomolecules. This paper contains supporting information that will be made available online once the issue is published. In the meantime, if you wish to get a copy of the supplementary file, please contact the Journals Editor, Sarah Brown, at [email protected]

Fuzzy Drug Targets: Disordered Proteins in the Drug-Discovery Realm.

Intrinsically disordered proteins (IDPs) and regions (IDRs) form a large part of the eukaryotic proteome. Contrary to the structure-function paradigm, the disordered proteins perform a myriad of functions in vivo. Consequently, they are involved in various disease pathways and are plausible drug targets. Unlike folded proteins, that have a defined structure and well carved out drug-binding pockets that can guide lead molecule selection, the disordered proteins require alternative drug-development methodologies that are based on an acceptable picture of their conformational ensemble. In this review, we discuss various experimental and computational techniques that contribute toward understanding IDP "structure" and describe representative pursuances toward IDP-targeting drug development. We also discuss ideas on developing rational drug design protocols targeting IDPs

Peptides for targeting βB2-crystallin fibrils

Crystallins are a major family of proteins located within the lens of the eye. Cataracts are thought to be due to the formation of insoluble fibrillar aggregates, which are largely composed of proteins from the crystallin family. Today the only cataract treatment that exists is surgery and this can be difficult to access for individuals in the developing world. Development of novel pharmacotherapeutic approaches for the treatment of cataract rests on the specific targeting of these structures. βB2-crystallin, a member of β-crystallin family, is a large component of the crystallin proteins within the lens, and as such was used to form model fibrils in vitro. Peptides were identified, using phage display techniques, that bound to these fibrils with high affinity. Fibrillation of recombinantly expressed human βB2-crystallin was performed in 10% (v/v) trifluoroethanol (TFE) solution (pH 2.0) at various temperatures, and its amyloid-like structure was confirmed using Thioflavin-T (ThT) assay, transmission electron microscopy (TEM), and X-ray fiber diffraction (XRFD) analysis. Affinity of identified phage-displayed peptides were analyzed using enzyme-linked immunosorbent assay (ELISA). Specific binding of a cyclic peptide (CKQFKDTTC) showed the highest affinity, which was confirmed using a competitive inhibition assay

Niosomal Drug Delivery Systems for Ocular Disease—Recent Advances and Future Prospects

The eye is a complex organ consisting of several protective barriers and particular defense mechanisms. Since this organ is exposed to various infections, genetic disorders, and visual impairments it is essential to provide necessary drugs through the appropriate delivery routes and vehicles. The topical route of administration, as the most commonly used approach, maybe inefficient due to low drug bioavailability. New generation safe, effective, and targeted drug delivery systems based on nanocarriers have the capability to circumvent limitations associated with the complex anatomy of the eye. Nanotechnology, through various nanoparticles like niosomes, liposomes, micelles, dendrimers, and different polymeric vesicles play an active role in ophthalmology and ocular drug delivery systems. Niosomes, which are nano-vesicles composed of non-ionic surfactants, are emerging nanocarriers in drug delivery applications due to their solution/storage stability and cost-effectiveness. Additionally, they are biocompatible, biodegradable, flexible in structure, and suitable for loading both hydrophobic and hydrophilic drugs. These characteristics make niosomes promising nanocarriers in the treatment of ocular diseases. Hereby, we review niosome based drug delivery approaches in ophthalmology starting with different preparation methods of niosomes, drug loading/release mechanisms, characterization techniques of niosome nanocarriers and eventually successful applications in the treatment of ocular disorders

Peptides to bridge biological-platinum materials interface

Peptides with inorganic materials recognition already started to impact a wide range of surface- related technologies ranging from biomonitoring to biomedical areas. Combinatorial biology- based libraries are the initial step in tempting the directed evolution of peptides with specifi c interactions towards technologically relevant materials. Here, a case study is provided to demonstrate the specifi c peptide binding and the amino acids residues that play an important role for platinum surface affi nity by combining computational as well as genetic engineering tools. Using a phage display technique, septapeptides were identifi ed exhibiting affi nity to noble metal platinum, and the amino acid distributions in the identifi ed peptides were analyzed. The analysis of the peptide sequences showed that strong Pt- binding peptides contain positively charged, hydrophilic, and polar residues, and especially enriched in threonine, serine, and glutamine. Under competitive surface- binding conditions, strong Pt- binding peptide motif displayed on phage resulted in high specifi city to Pt regions on a Pt- macropatterned glass. Conformational analysis of the strong binder indicates that threonine and serine as well as glutamine are in close contact with the surfaces forming a tripod molecular architecture. The alanine substitution mutagenesis applied at the genomic level to the peptide displayed on the phage revealed threonine and serine substitutions as the critical ones. Understanding the residue- based interactions of the peptide sequences can be utilized to tune the affi nity and the specifi city of the peptides with the inorganic surfaces, toward making them indispensable molecular tools to control the molecular interactions of biological macromolecules with the material surfaces