TABLE 5.

The effect of mutants of Phormidium cytochrome f on their interaction with Phormidium PC in the absence of Zn²⁺

Class*	Mutant†	Complexes formed per 1000 trajectories†	% WT	10−8 × k2 (M−1 s−1)†
	Q7E	23.3 ± 0.6	114	6.7 ± 0.7
	WT	20.4 ± 0.5	100	5.9 ± 0.3
II	Complex formation between 59 and 77% WT
	E92A	14.7 ± 0.7	72	4.3 ± 0.4
	E217A	13.0 ± 0.5	63	3.8 ± 0.3
	D199A	12.6 ± 0.3	62	3.6 ± 0.3
	Q7R	12.6 ± 0.2	62	3.7 ± 0.3
III	Complex formation between 50 and 59% WT
	E192A	11.6 ± 0.3	57	3.4 ± 0.4
	D42A	11.6 ± 0.6	57	3.4 ± 0.3
	D205A	11.4 ± 0.3	56	3.4 ± 0.4
	D87A	11.0 ± 0.4	54	3.2 ± 0.4
	E79A	11.0 ± 0.2	54	3.2 ± 0.3
	D109A	10.6 ± 0.5	52	3.1 ± 0.3
	E95A	10.6 ± 0.2	52	3.1 ± 0.3
	E14A	10.5 ± 0.4	51	3.1 ± 0.4
IV	Complex formation between 44 and 48% WT
	D122A	9.8 ± 0.5	48	2.9 ± 0.3
	E91A	9.6 ± 0.4	47	2.6 ± 0.3
	E123A	9.5 ± 0.2	46	2.7 ± 0.3
	D63A	9.1 ± 0.2	45	2.7 ± 0.2
	E86A	9.0 ± 0.4	44	2.7 ± 0.3
V	Complex formation <40% WT
	D187A	7.2 ± 0.3	35	2.1 ± 0.3
	E165A	6.8 ± 0.3	33	2.0 ± 0.3
	D188A	6.5 ± 0.2	32	2.0 ± 0.3

^*Class II: the number of complexes was between 59 and 77% WT; class III: 50–59% WT; class IV: 44–48% WT; and class V: ≤35% WT. Note that the same class divisions were used for Tables 4 and 5 for ease of comparison.

^†The mutants were made as described in the Methods section. The number of complexes formed and the rates of electron transfer were calculated as described for Table 1 and in the Methods section.