3.7 Cryo-EM Structure of the Core Centromere Binding Factor 3 Complex

Abstract

The Centromere Binding Factor 3 (CBF3) complex binds the third Centromere DNA Element in organisms with point centromeres, such as S. cerevisiae. It is the only essential centromere binding complex as it facilitates genetic specification of point centromeres. It is therefore the most fundamental complex of the kinetochore in these organisms and its association with centromere DNA allows association of all other kinetochore components. We have determined the atomic structure of the core complex of CBF3, comprising 3 of its 4 components, using cryo-EM. The architecture of the complex is ‘U’-shaped, with a deep, strongly basic channel that is narrow at one end and wide at the other. Combining our structure and in vitro assays, we present a model for its association with centromere DNA.