Table 2.

Bond lengths and bond angles for the N₃-Fe³⁺SOD active site as determined by X-ray crystallography (PDB file 1ISC) as well as for the QM/MM optimized structures of N₃-Fe³⁺SOD, Q69E N₃-Fe³⁺SOD, N₃-Fe³⁺(Mn)SOD, and Y34F N₃-Fe³⁺(Mn)SOD

	1ISCa	N3-Fe3+SOD	Q69E N3-Fe3+SOD	N3-Fe3+(Mn)SOD	Y34F N3-Fe3+(Mn)SOD
Bond lengths (Å)
Fe–N(azide)	2.12	2.13	2.11	2.19	2.11
Fe–O (Sol)	2.00	1.89	1.97	1.89	1.90
Fe–O (Asp)	2.03	2.01	1.98	1.98	2.01
Fe–N (His26)	2.22	2.28	2.31	2.21	2.21
Fe–N (His160)	2.16	2.23	2.19	2.22	2.25
Fe–N (His73)	2.13	2.14	2.14	2.22	2.24
H-bond distances (Å)
O(Sol)⋯N(Gln)/O(Glu)	3.29	3.27	2.65	2.82	2.75
O(Sol)⋯O(Asp)	3.15	2.91	3.35	2.78	2.78
O(Tyr)⋯N(Gln)/O(Glu)	3.04	3.58	3.06	3.12
O(Gln/Glu)···N(Trp)	3.08	2.83	2.81	2.83	2.90
Bond angles (deg)
Fe–N–N	117	126	125	121	123
N3–Fe–O(Sol)	115	94	100	71	71
His–Fe–His	161	161	163	161	163

^aParameters taken from PDB file 1ISC, ref 6.