Table 1.

Kinetic parameters of electron transfer in the mutant strains

Strain	A oxidation				Amplitude* (% of total)	P reduction, t430 nm (μs)
	Fast phase		Slow phase
	t380 nm (ns)	t480–457 nm (ns)	t380 nm (ns)	t480–457 nm (ns)
Control	13  ± 2	13  ± 3	143  ± 10	160  ± 11	34  ± 3	4.0  ± 0.2
PsaA–W693F	15  ± 2	12  ± 3	490  ± 21	355  ± 120	34  ± 2	4.0  ± 0.2
PsaB–W673F	73†	62†	143†	160†	33  ± 10	4.2  ± 0.3
W693F/W673F	73  ± 17	62  ± 28	485  ± 70	350  ± 100	49  ± 9	4.1  ± 0.2
PsaA–E695Q	11  ± 5	n.d.	277  ± 33	n.d.	44  ± 11	4.4  ± 0.3
PsaA–E698Q	11  ± 4	n.d.	222  ± 30	n.d.	36  ± 10	3.9  ± 0.2
W702F/W682F	19  ± 12	n.d.	187  ± 28	n.d.	n.d.	3.9  ± 0.2

The half-times (t) were estimated from the data using fits to one or two exponential decay components. The measurement at 380 nm is in the spectral region of the semiphylloquinone absorption, the difference 480–457 nm is in the electrochromic band shift induced by the presence of charge on A₁. The half-time of P₇₀₀ re-reduction was calculated from the decay of the absorption change at 430 nm. n.d., not determined. 

^*The relative amplitude of the fast nanosecond phase expressed as percentage of the total amplitude was estimated from the kinetics at 380 nm. Values that are significantly different from those of the control strain are in bold. 

^† The half-times of the two phases used to fit the data for PsaB–W673F strain were fixed parameters with values taken from the double mutant for the fast phase and from the control strain for the slow phase, as described in the text.