Project title: Elucidating the assembly and molecular architecture of the conjugative relaxosome complex
Summary: Antibiotic resistance in bacteria is predicted to be the cause of 10 million human deaths annually by the year 2050. Research into mechanisms behind the key cellular machinery that bacteria utilise in overcoming antibiotic lethality is vital in tackling this crisis.
Horizontal gene transfer (HGT) is the method by which genetic information, in the form of plasmid DNA, is shared within a bacterial population. HGT is a major target of novel antimicrobial developments; genes that facilitate drug resistance in bacterial cells are frequently encoded within this distributed genetic information.
In Escherichia coli, the machinery of the relaxosome complex is expressed in response to external signals such as pH, temperature, and nutrient composition, and undertakes a sequence of processing events on plasmid DNA containing the specific transfer signal oriT. The relaxosome works with the Type IV Secretion System to transfer this DNA into a recipient cell via the pilus- a process known as bacterial conjugation.
In this project, I aim to elucidate the architecture of the relaxosome complex using Cryo-Electron Microscopy (Cryo-EM). This would be used to investigate interactions between the key proteinaceous components of the relaxosome and the DNA for transfer. I also aim to investigate the environmental influences that favour the assembly of the relaxosome using RNA-FISH.