Construction of a signal peptide library and evaluation of effects of different signal peptides on the secretion of recombinant proteins in Aspergillus nidulans.

• Grant number: 24/01154-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2024
• End date: February 28, 2026
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Fernando Segato
• Grantee: Pedro Ribeiro Faria
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil
• Associated research grant: 20/07015-7 - PBIS - Integrated Biotechnological Platform of Healthy Ingredients, AP.NPOP

Abstract

Filamentous fungi are recombinant protein expression platforms of growing biotechnological interest. Their potent secretory pathways and highly competent cellular machinery show great potential for the development of expression systems capable of yielding several different recombinant proteins of both industrial and commercial interest. One of the main approaches in the obtention of recombinant proteins of filamentous fungi is the fusion of signal peptides, pre-sequences or carrier domains to the N-terminal of the client proteins, enhancing the secretion of synthesized proteins, with no down sides to its structure, folding or other post-translational modifications, turning filamentous fungi into efficient cell-factories for the production hard-to-get recombinant proteins. Thaumatin is a sweet protein of growing interest in the pharmaceutical and food industries, and is a notably hard-to-get protein through its natural source, requiring large amounts of the Thaumatococcus danielli fruits to be processed in order to obtain milligrams of the product, making the possibility of obtaining the protein from a recombinant platform very attractive. This approach has already been explored by some groups, though with low yields of protein, in the range of a few milligrams per liter of fermentation media. It has been reported a possible relation of thaumatin's native pre-sequence to its integrity and efficient secretion in recombinant strains of filamentous fungi. The investigation of this relation and the investigation of the influence of different leader sequences on the integrity and secretion of functional and structurally sound proteins is the goal of this project, utilizing fluorescent chromophores to elucidate the synthesis, transit, integrity, packaging and secretion of recombinant thaumatin, as well as investigating the potency of different leader sequences, making it also possible to develop a new library of leader sequences, which can be further developed into new commercial products, aimed at the development of recombinant proteins expression systems based of filamentous fungi.