using protein scaffold vs carrier protein

The actively transported molecule is shown in yellow, and the energy source is shown in red. As with enzymes, the binding of solute can be blocked specifically by either competitive inhibitors (which compete for the same binding site and may or may not be transported by the carrier) or noncompetitive inhibitors (which bind elsewhere and specifically alter the structure of the carrier).

In addition, each transporter protein has a characteristic binding constant for its solute, K m, equal to the concentration of solute when the transport rate is half its maximum value ( Figure 11-7). This rate, referred to as V max, is characteristic of the specific carrier and reflects the rate with which the carrier can flip between its two conformational states. When the carrier is saturated (that is, when all solute-binding sites are occupied), the rate of transport is maximal. A schematic model of how such a carrier protein is thought to operate is shown in Figure 11-6.

It transfers the solute across the lipid bilayer by undergoing reversible conformational changes that alternately expose the solute- binding site first on one side of the membrane and then on the other. In contrast to ordinary enzyme-substrate reactions, however, the transported solute is not covalently modified by the carrier protein, but instead is delivered unchanged to the other side of the membrane.Įach type of carrier protein has one or more specific binding sites for its solute ( substrate). Published by Elsevier B.V.The process by which a carrier protein transfers a solute molecule across the lipid bilayer resembles an enzyme- substrate reaction, and in many ways carriers behave like enzymes. Based on the above findings, the ssPalmE-KALA appears to be a potent ex vivo DCs-based RNA vaccine platform.Ĭancer immunotherapy Lipoplex Proteomics RNA vaccine.Ĭopyright © 2019. In parallel, the vaccination induced significant prophylactic anti-tumor effects against a model tumor that stably expressed the OVA protein. In the vaccination with the BMDCs that were preliminarily transfected with an ovalbumin (OVA)-encoding mRNA elicited the induction OVA specific cytotoxic T-lymphocyte activity in vivo. Proteomic analyses suggest that transfection with the ssPalmM-KALA stimulates a down-regulatory pathway of translation, while the transfection with the ssPalmE-KALA does not stimulate it. A cellular uptake process and a pH-responsive membrane-destabilization activity cannot explain the preferred protein expression and immune-stimulation caused by the ssPalmE-KALA. The transfection of mRNAs complexed with the ssPalmE-KALA achieved a significantly higher protein expression and the production of proinflammatory cytokines from murine bone marrow derived DCs (BMDCs) in comparison with a lipoplex that was prepared with an ssPalm with fatty acid-scaffolds (myristic acid ssPalmM-KALA). In the present study, we report on the development of a lipoplex-type mRNA carrier for use as a DC-vaccine by using a combination of an ssPalmE-LNP and an α-helical cationic peptide 'KALA' (ssPalmE-KALA). We previously reported on an ionizable lipid-like material with vitamin E-scaffolds (ssPalmE) as a material for a lipid nanoparticle (LNP)-based carrier for nucleic acids.

In order to introduce an antigen, a carrier for mRNA transfection is required, since the mRNA molecule per se is unstable in serum-containing medium. For the insertion of a foreign antigen to DCs, the transfection of an antigen-coding mRNA to the cells is a promising approach. A dendritic cells (DCs)-based vaccine (DC-vaccine) system is an attractive technology for eliciting antigen-specific immune responses that can protect subjects from infectious diseases and for curing various types of cancers.

Using protein scaffold vs carrier protein