Figure 1.

Calcium ions affect the conformation of human DMC1

(A) CD spectra of the human DMC1 protein (5 μM) in the presence of ATP (0.3 mM) and absence of calcium ions (light blue line), or in the presence of 1-mM CaCl₂ (green line).

(B) 2D class averages of cryo-EM particles of human DMC1 protein in the presence of MgCl₂ and ATP representing “opened” (a, b, and c), “intermediate” (d), “closed” (e), and “lobe” (f) states. (C) 2D class averages of cryo-EM particles of human DMC1 protein in the presence of CaCl₂ and ATP illustrating “opened” (a), “intermediate” (b), and “lobe” (c) states. Classification of individual states was based on RGB scale in range from 0 (black color) to 255 (white color), respectively. The intensity in RGB scale 1–50 corresponds to opened, 51–100 to intermediate, 101–200 to closed, and 201–300 to lobe forms, respectively. See also Figure S1.