Our group has long-time experience in the study of the structure and folding of proteins from a basic point of view, but always with a view to the biotechnological application of the results. More specifically, we are interested in engineering bioaffinity interactions between recombinant proteins and supports (liquid or solid) with the aim of developing new systems for immobilization and purification of proteins. These functionalized supports, in turn, can be used as enzymatic bioreactors to carry out chemical biotransformations, or to construct carrier / delivery systems for peptides or proteins of biotechnological and biomedical interest.
To achieve the above goals, we make use of two affinity tags:
1.- Choline-binding modules (CBMs). They are polypeptide structures with high affinity for supports functionalized with tertiary or quaternary aliphatic amines (e.g. DEAE). Fusion proteins containing CBMs such as C-LytA can be immobilized from an overproducing bacterial extract, and be maintained in such a estate even after extensive washing with high ionic strength. Then, the immobilized protein can be used directly or eluted by the simple addition of choline. Such aminated resins are very common in biochemistry and molecular biology laboratories, they are usually inexpensive and can be found in a wide variety of formats: chromatographic resins, paper, multiwell plates, nanoparticles, etc. Furthermore, we have developed an aqueous two-phase system that allows CBM-containing proteins to be purified by a procedure without the aid of solid chromatography.
2.- BioF tag. In collaboration with the laboratory of Dr. Auxi Prieto (CIB), we are employing the BioF tag, developed in her laboratory, to biophysically analyze its interaction with bioplastics of the polyhydroxyalkanoate (PHA) type. As a result, we are setting the conditions to use PHA as a biocompatible, controlled-release system for peptides and proteins, with a view to biomedical applications. Moreover, we have recently constructed a bioplastic-based enzymatic minireactor capable of decolorizing wastewaters from the textile industry, which constitutes a proof-of-concept to illustrate the potential of the PHA-BioF system in biotechnology.