Molecular insights in how immune pores kill Gram-negative bacteria

Dennis Doorduijn

My research focuses on how pores formed by the complement system, an important family of plasma proteins of the innate immune system, kill Gram-negative bacteria. This pore, the Membrane Attack Complex (MAC), is formed when bacteria are recognized by the complement system which triggers a proteolytic cascade at the bacterial surface. This  results in the labelling of bacteria with convertase enzymes that can ultimately initiate the assembly of a MAC pore. In my PhD project, I aim to better understand on a molecular level how this enzyme and the MAC pore interact at the bacterial surface and how this leads to specific killing of bacteria. This question I aim to answer by using a combination of flow cytometry and biochemical protein analyses to analyze what protein interactions at the surface are essential to generate a lethal MAC pore. As second goal of my PhD project, I aim to better understand how these pores actually lyse the bacterial cell wall and subsequently kill the bacterium. This question I aim to answer by using high resolution microscopy on bacteria labelled with pores, such as atomic force microscopy and (cryo-)electron microscopy. Understanding these fundamental aspects of how MAC pores kill Gram-negative bacteria can ultimately give us insight in how bacteria evade killing by the immune system and potentially help us in fine-tuning antibacterial (immune) therapy accordingly.

Flow cytometry, molecular biological techniques (Gibson, PCR, cloning), recombinant protein production and modification, biochemical protein analyses (SDS-PAGE/SEC/FPLC), confocal microscopy, (cryo-)electron microscopy, atomic force microscopy