Kmn1, Mis12 and either Nnf1a or Nnf1b were coexpressed in E. coli (otherwise proteins were insoluble), then purified by gel filtration. The complex was then treated with BS2G bi-functional crosslinking reagent, and cross-links were mapped by mass spectrometry.
Within either the Kmn1-Mis12-Nnf1a or Kmn1-Mis12-Nnf1b trimeric complexes, all three subunits make extensive contacts with each other, extending along their entire sequences.
Interaction in vitro; proteins produced as a recombinant fusion proteins in bacterial system.