Structural and functional characterization of the complex involved in dsDNA packaging in Caudoviricetes bacteriophages

• Grant number: 25/12927-9
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2025
• End date: July 31, 2029
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Principal Investigator: Germán Gustavo Sgro
• Grantee: Jairo Herlan Dominguez Antty
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 22/03018-7 - Structural, molecular and functional characterization of bacteriophages associated with bacteria of medical and agricultural interest, AP.PNGP.PI

Abstract

Bacteriophages from the Caudoviricetes class play a key role in microbial dynamics and hold great biotechnological potential, particularly in the context of phage therapy. A critical step in the lytic cycle of these viruses is the packaging of viral DNA into the capsid, a process mediated by the terminase complex. This project aims to structurally and functionally characterize the terminases of representative phages from the Podoviridae, Siphoviridae, and Myoviridae families, isolated in the proponent's laboratory. The experimental approach includes heterologous cloning and expression of terminase-coding genes, purification of the subunits, and analysis of DNA interactions using biochemical and biophysical techniques (such as EMSA, ITC, and DSF), as well as ATPase and endonuclease activity assays. Structural analysis will be carried out through negative-staining transmission electron microscopy and cryo-electron microscopy (cryo-EM). This project is expected to generate both structural and functional data that will allow comparison of the molecular mechanisms used by terminases from different viral families, thereby contributing to the understanding of DNA packaging strategies in phages and opening new avenues for the application of these proteins in biotechnology and virus-based therapies. (AU)