Table 1.

Key interatomic distances (in Å) and relative Gibbs free energies (in kcal/mol) for different HPPD complexes.

Complex∗	Interatomic distances					Grel	RMSD †
	D1	D2	D3	D4	D5
HPPD(Co2+)-HPPA(enol)	2.210	2.032	1.421	1.334	1.523	0.00	0.141
HPPD(Co2+)-HPPA(ketone)	2.218	2.134	1.243	1.541	1.579	-19.26 ‡	0.043
HPPD(Fe2+)-HPPA(enol)	2.276	2.021	2.392	1.321	1.510	0.0	0.551
HPPD(Fe2+)-HPPA(ketone)	2.317	2.142	1.220	1.512	1.574	-13.27 §	0.073
Exp.	2.171	2.098	1.185	1.529	1.530		0.000

^∗ The naming of complexes and interatomic distances are described in Figure 2.

^† The RMSD (in Å) of the calculated distances (D1 to D5) from those in the X-ray crystal structure.

^‡ Calculated by using the HPPD(Co²⁺)-HPPA(enol) complex as reference.

^§ Calculated by using the HPPD(Fe²⁺)-HPPA(enol) complex as reference.