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. 2018 Jul 24;74(Pt 8):800–813. doi: 10.1107/S2059798318004588

Figure 5.

Figure 5

Illustration of PDB format for an exchanged amide H atom in an arginine residue (residue 38 of chain A). All three possibilities describe the same configuration: one H atom with occupancy q H = 0.77 and a D atom with complementary occupancy q D = 1 − q H = 0.23. Top, method (i), using double conformation and different atom names. Middle, method (ii), implying the D atom with q D = 1 − q H. Bottom, method (iii), using an apparent occupancy. The occupancy mimics the total scattering contributions of the H and D atoms, which are of different signs, and varies from −0.56 (H fully occupied) to 1 (D fully occupied).