Insoluble proteins catch heterologous soluble proteins into inclusion bodies by intermolecular interaction of aggregating peptides.

Abstract

Background: Protein aggregation is a biological event observed in expression systems in which the recombinant protein is produced under stressful conditions surpassing the homeostasis of the protein quality control system. In addition, protein aggregation is related to conformational diseases in animals as transmissible prion diseases, and non-transmissible neurodegenerative diseases including Alzheimer, Parkinson's disease, amyloidosis and multiple system atrophy among others. At the molecular level, the presence of aggregating-prone domains in protein molecules act as seeding igniters to induce the accumulation of protein molecules in protease-resistant clusters by intermolecular interactions.Results: In this work the aggregating-prone performance of a small peptide (L6K2) with additional antimicrobial activity was studied and the relevance of the accompanying scaffold protein to enhance the aggregating profile of the fusion protein has been elucidated. Furthermore, it was demonstrated that the fusion of L6K2 to highly soluble recombinant proteins directs the protein to inclusion bodies (IBs) in E. coli through stereospecific interactions in the presence of an insoluble protein displaying the same aggregating-prone peptide (APP). Conclusions: These data suggest that the molecular bases of protein aggregation are related not only to the presence of aggregation-prone stretches, but to the net balance of protein aggregation potential. and not only to the presence of aggregation-prone stretches. This is ultimately presented as a generic platform to generate hybrid protein aggregates in microbial cell factories for biopharmaceutical and biotechnological applications.