. 2023 Nov 21;62(48):19433–19445. doi: 10.1021/acs.inorgchem.3c02329

Table 3. Quality Measures and Fe–O Distances (d in Å) for the Four Quantum-Refined Structures with Varying Protonation States of Homocitrate (cf. Figure 2)^a.

	RSZD	RSR	RSCC	ΔE_str (kJ/mol)	ΣΔd (Å)	d(Fe–O)_QR		d(Fe–O)_QM
						O5	O7	O5	O7
2H	1.1	0.046	0.962	35	0.08	2.22	2.21	2.23	2.28
1Ha	0.5	0.044	0.967	41	0.07	2.17	2.20	2.13	2.23
1Hc	1.7	0.050	0.955	54	0.08	2.23	2.13	2.22	2.06
0H	2.8	0.055	0.944	38	0.10	2.22	2.06	2.19	1.99

The quality measures are the real-space Z-scores based on the difference maps (RSZD), the real-space R factors (RSR), the real-space correlation coefficients (RSCC) for homocitrate, the strain energy of the QM region (ΔE_str), and the sum of the difference in the Fe–O bond lengths (ΣΔd) to the homocitrate O5 (carboxylate) and O7 (alcohol) atoms in the quantum-refined structure [d(Fe–O)_QR] and in a structure optimized by QM/MM without any crystallographic information [d(Fe–O)_QM]. The best results of each quality measure are marked in bold face.

Table 3. Quality Measures and Fe–O Distances (d in Å) for the Four Quantum-Refined Structures with Varying Protonation States of Homocitrate (cf. Figure 2)a.

Table 3. Quality Measures and Fe–O Distances (d in Å) for the Four Quantum-Refined Structures with Varying Protonation States of Homocitrate (cf. Figure 2)^a.