Crosslinking mass spectrometry of the unconventional kinetoplastid kinetochore protein KKT4

The kinetochore is the macromolecular protein machine that drives chromosome segregation by interacting with spindle microtubules. Unlike most other eukaryotes that have canonical kinetochore proteins, a group of evolutionarily divergent eukaryotes called kinetoplastids (such as Trypanosoma brucei that causes human African trypanosomiasis) have a unique set of kinetochore proteins. To date, the only kinetoplastid kinetochore protein that is known to bind microtubules is KKT4, which has no high-resolution structure information available. Here we used X-ray crystallography, NMR spectroscopy, and crosslinking mass spectrometry to characterise the structure and dynamics of KKT4.