Expression and purification of recombinant TAT-BoNT/A(1-448) under denaturing and native conditions

Novel Native and Engineered Botulinum Neurotoxins

Botulinum neurotoxins (BoNTs), produced by Clostridia and other bacteria, are the most potent toxins known. Their cleavage of the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) proteins in neurons prevents the release of neurotransmitters, thus resulting in the muscle paralysis that is characteristic of botulism. This mechanism of action has been exploited for a variety of therapeutic and cosmetic applications of BoNTs. This chapter provides an overview of the native BoNTs, including the classical serotypes and their clinical use, mosaic BoNTs, and novel BoNTs that have been recently identified in clostridial and non-clostridial strains. In addition, the modular structure of native BoNTs, which are composed of a light chain and a heavy chain, is amenable to a multitude of novel fusions and mutations using molecular biology techniques. These novel recombinant BoNTs have been used or are being developed to further characterize the biology of toxins, to assist in vaccine production, to serve as delivery vehicles to neurons, and to be utilized as novel therapeutics for both neuronal and non-neuronal cells.

Expression and Purification of Extracellular Solute-Binding Protein (ESBP) in Escherichia coli, the Extracellular Protein Derived from Bifidobacterium longum KACC 91563

Bifidobacterium longum KACC 91563 secretes family 5 extracellular solute-binding protein via extracellular vesicle. In our previous work, it was demonstrated that the protein effectively alleviated food allergy symptoms via mast cell specific apoptosis, and it has revealed a therapeutic potential of this protein in allergy treatment. In the present study, we cloned the gene encoding extracellular solute-binding protein of the strain into the histidine-tagged pET-28a(+) vector and transformed the resulting plasmid into the Escherichia coli strain BL21 (DE3). The histidine-tagged extracellular solute-binding protein expressed in the transformed cells was purified using Ni-NTA affinity column. To enhance the efficiency of the protein purification, three parameters were optimized; the host bacterial strain, the culturing and induction temperature, and the purification protocol. After the process, two liters of transformed culture produced 7.15 mg of the recombinant proteins. This is the first study describing the production of extracellular solute-binding protein of probiotic bacteria. Establishment of large-scale production strategy for the protein will further contribute to the development of functional foods and potential alternative treatments for allergies.

The Expanding Therapeutic Utility of Botulinum Neurotoxins

Botulinum neurotoxin (BoNT) is a major therapeutic agent that is licensed in neurological indications, such as dystonia and spasticity. The BoNT family, which is produced in nature by clostridial bacteria, comprises several pharmacologically distinct proteins with distinct properties. In this review, we present an overview of the current therapeutic landscape and explore the diversity of BoNT proteins as future therapeutics. In recent years, novel indications have emerged in the fields of pain, migraine, overactive bladder, osteoarthritis, and wound healing. The study of biological effects distal to the injection site could provide future opportunities for disease-tailored BoNT therapies. However, there are some challenges in the pharmaceutical development of BoNTs, such as liquid and slow-release BoNT formulations; and, transdermal, transurothelial, and transepithelial delivery. Innovative approaches in the areas of formulation and delivery, together with highly sensitive analytical tools, will be key for the success of next generation BoNT clinical products.