Figure 4.

Crystal Structure of Ycg1–Brn1 in Complex with DNA

(A) Cartoon and surface models of the Sc Ycg1–Brn1 complex bound to an 18-bp dsDNA substrate and to the 18-bp dsDNA of its symmetry-related neighbor, based on the Sc Ycg1_{6–498, 556–932}–Brn1_384–529 construct. The ends of the disordered region of Sc Brn1 (red circles), the Brn1 kleisin disordered linker, α₄ buckle, and α₁ latch regions are indicated.

(B) Close-up views of the Sc Ycg1–Brn1 interaction with DNA.

(C) Schematic illustrations of the main contacts of Sc Ycg1 and Brn1 residues with the 18-bp DNAs in crystal forms I and II. Highly conserved residues are shown in bold, distant residues are shown in opaque. The length of the lines is proportional to the observed distances of H-bonds (solid lines) or ionic interactions (dotted lines).

(D) Structural alignment of Sc Ycg1–Brn1 and Sc Ycg1–Brn1–DNA (crystal form I) using all C_α atoms (RMSD 1.95 Å over 820 C_α). Arrows indicate conformational differences in the N-terminal shoulder region of Ycg1. Close-up views highlight changes of side chains in the Brn1 latch region.

(E) Structural alignment of Sc Ycg1–Brn1–DNA crystal forms I and II DNA using all C_α atoms (RMSD 0.79 Å over 685 C_α). Arrows indicate conformational differences in the DNA and in the C-terminal shoulder region of Ycg1.

See also Figure S5.