Extended Data Fig. 6: Data and model quality of the Mec1(F2244L)-Ddc2 reconstruction.

a, Map to model FSC curves of the F2244 mutant reconstruction. b, Ddc2 and Mec1 N-terminal domain density (NTD) and model showing clear separation of Mec1 and Ddc2 proteins for accurate model building of this region (left), with close-up views of chain tracing between the model built in this study (middle) and the previously published model (PDB:5X6O) (right). The arrow indicates the point at which the two models diverge. c, High-resolution features from the 2.8 Å map, showing that the electron density quality is sufficient to resolve types of aromatic residues (Phenylalanine over Tyrosines), β−branched side chains (Isoleucine), as well as smaller hydrophobics (Valine) and an example of a split conformation of Arginine. d-f, CryoEM density regions of the Mec1 N-terminal domain (~300 amino acids) showing the overall fit of the model and side chains (labeled), along with close-up views of different regions showing unambiguous side chain density for accurate model building.