Heterologous Expression, Structural Characterization, and Bioactivity Evaluation of Antarctic-Derived Ribosomally Synthesized and Post-Translationally Modified Peptides

• Grant number: 25/14643-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: November 01, 2025
• End date: October 31, 2027
• Field of knowledge: Biological Sciences - Biochemistry - Biochemistry of Microorganisms
• Principal Investigator: Elizabeth Bilsland
• Grantee: William Bartolomeu de Medeiros
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The rapid rise of antimicrobial resistance underscores the urgent need to discover novel antibiotics with unique mechanisms of action. Ribosomally synthesized and post-translationally modified peptides (RiPPs) have emerged as promising candidates, particularly those derived from microorganisms adapted to extreme environments. This project aims to heterologously express and chemically and functionally characterize two biosynthetic gene clusters (BGCs) encoding a lasso peptide and a lanthipeptide, both mined from Antarctic metagenomes generated during the FAPESP-funded PhD project (grant number 2020/11534-0). These BGCs were prioritized based on the presence of key biosynthetic elements, including genes encoding the precursor peptide, post-translational modification enzymes, ABC transporters, and a putative self-resistance gene. The lasso peptide BGC has already been engineered, cloned into the pCAP03 vector, and transformed into Escherichia coli, demonstrating the feasibility of the proposed heterologous expression strategy. In contrast, the lanthipeptide BGC has already been engineered in silico for direct cloning into the pET28a(+) expression vector containing an inducible T7 promoter, promising an optimized workflow and enabling precise expression control. This project combines the untapped biosynthetic potential of the Antarctic microbiome with synthetic biology approaches to access and evaluate novel RiPPs. The outcomes are expected to expand our understanding of RiPP diversity in extreme environments and identify new antimicrobial compounds with therapeutic relevance in the fight against multidrug-resistant pathogens.