Table 3.

QM/MM models

	X-ray†	X-ray‡	R§	TS¶	P‖
NAdoMet-Fe4*	2.33	2.26	2.30	2.24	2.25
OAdoMet-Fe4*	2.25	2.27	2.15	2.13	2.14
Sδ-Fe4*	3.25	2.67	3.20	2.62	2.63
Sδ-C5′	1.82	3.78	1.84	3.33	4.00
Sδ-S3*	3.66	3.50	3.70	3.61	3.58
S3*-Fe4*	2.28	2.35	2.42	2.48	2.47
S1-Fe4*	2.25	2.39	2.58	2.61	2.62
S4-Fe4*	2.33	2.44	2.43	2.60	2.62

Key distances (ångstoms) in the active site for the reactant (R = AdoMet-bound HydE), the transition state (TS) and the product (P = [5′-dA·+ Met]-bound HydE) compared to X-ray (see Fig. 1 for atom labels).

^†X-ray model of AdoMet-bound to HydE.

^‡X-ray model of [5′-dA· + Met]-bound to HydE.

^§QM/MM optimize structure of R.

^¶QM/MM optimized structure of TS.

^‖QM/MM optimized structure of P.