Table 3. Reduction potentials for T1Cu and T2Cu centres in wild-type AxNiR and F306C.

	T1Cu (mV)	T2Cu (mV)pH 7	T2Cu (mV)pH 5.8
WT AxNiR	255±3*	244±18*	260±15
F306C	262±3	269±10	210±15

NO₂, nitrite; r.m.s.d., root mean square deviation; T1Cu, type-1 Cu; T2Cu, type-2 Cu; WT, wild type.

^*Values are taken from ref. 7. Values shown for T1Cu and T2Cu at pH 7 are obtained after fitting the data sets from a single experiment to the Nernst equation. Since the T1Cu reduction potential is pH independent16, the values for T2Cu at pH 5.8 were calculated from the relative absorbance recovery in the flash-photolysis experiments performed at pH 5.8.