Table 2.

Optimised parameters (bond lengths, force constants, charges) and geometry in WT and the eight mutant systems in Group 4. In brackets are values from the crystal structure. * values are in kcal/mol, and ** indicates parameter values from Tyr (mutation) in the MBS enviroment.

	System	WT	D49A	D49G	H51P	H51R	H51Y	H57P	H57Y	H71R
bo (Å)	D49OD2	1.96 (2.15)	–	–	1.92	1.92	1.90	1.90	1.95	1.92
	H51NE2	1.95 (2.30)	1.94	1.94	–	–	2.00**	1.90	1.96	1.95
	H57NE2	1.88 (2.32)	1.96	1.96	1.95	1.95	2.00	–	2.01**	1.95
	H71NE2	2.01 (2.23)	1.92	1.92	1.95	1.95	1.96	1.93	1.97	–
Kb *	D49OD2	70.30	–	–	138.30	138.20	129.00	132.20	110.80	136.9
	H51NE2	108.59	124.60	124.60	–	–	65.80**	129.50	91.20	114.2
	H57NE2	132.70	108.30	108.30	104.70	104.70	74.30	–	48.00**	106.4
	H71NE2	82.60	124.00	124.00	110.10	110.10	103.40	112.00	78.80	–
Charge	Fe2+	0.59 (2.00)	1.13	1.14	1.04	1.03	0.62	1.08	0.33	1.07
	D49OD2	−0.47	–	–	−0.64	−0.63	−0.52	−0.68	−0.55	−0.56
	H51NE2	0.01	−0.34	−0.35	–	–	−0.57**	−0.36	−0.04	−0.59
	H57NE2	−0.15	−0.84	−0.84	−0.54	0.10	−0.34	–	−0.57**	−0.56
	H71NE2	−0.18	−0.43	−0.43	−0.57	−049	−0.25	−0.31	−0.17	–
Geometry	MBS	Octahedral (distorted)	Square pyramidal		Square planar	Trigonal bi-pyramidal	Square planar	Square pyramidal