Elucidating the structure and function of the β-propeller of Erb1 in the context of Nop7-Erb1-Ytm1 complex

Abstract

Although it has been proposed that the C-terminal WD40 domain of Erb1 is dispensable for Nop7-Erb1-Ytm1 trimer assembly, here we show the crystal structure of the dimer formed by full-length Ytm1 bound to the β-propeller domain of Erb1 from Chaetomium thermophilum (ChYtm1 and ChErb1432-801 respectively). The structural findings have been confirmed in vitro using affinity co-purification, gel filtration, interferometry and ITC. Generation of a mutant β-propeller of ChErb1 that binds ChYtm1 less efficiently further evidences its importance in the dimer formation. Moreover, we prove that an analogous mutation affects ribosome biogenesis in yeast.