Colicin structural biology and function

Colicins are toxic proteins excreted by some members of the family Enterobacteriaceae. They typically have a narrow-spectum killing ability, and in nature, are a defense mechanism by which a bacterium can defend its niche against other bacteria. With the current worldwide increase in antibiotic resistance, colicins are interesting as next-generation antibiotics. Further, they are highly specific against only certain strains of bacteria, and thus not potentially as lethal against the natural human bacterial flora, increasing their attractiveness as highly specific antibiotics.

Figure 1. Colicin translocation across the outer and inner membrane and killing mechanism. Colicins recognize outer membrane proteins on the bacterial surface, which they use to cross the outer membrane. From there, they can directly exert their killing mechanism on the inner membrane by forming pores, or transport themselves across the inner membrane and act as nucleases within the cytoplasm.

 

In this project, we wish to structurally and functionally characterize a number of colicins, one of which we expect to be structurally distinct from any other known colicin structure to date. A number of functional assays are now established in the lab, and in the case of at least one colicin, we have a well-established expression and purification protocol that gives enough purified protein for both structural and functional studies. With the colicin that is predicted to be structurally distinct, a substantial amount of optimization towards its growth and purification conditions has also been completed. 

The student on this project will learn a variety of techniques, including:

  • Protein expression and purification
  • In vivo functional assay design
  • Structural methods, including X-ray crystallography and/or NMR

The student will be closely supervised by PhDs and Postdocs currently in the group, and will be trained in all methods necessary to complete the work. MSc candidates for this project are expected to bring good theoretical knowledge in biochemistry, molecular biology and/or microbiology.

Published Apr. 19, 2018 8:13 AM - Last modified July 16, 2018 12:57 PM

Supervisor(s)

Scope (credits)

60