Table 2.
(B)Chl lifetimes bound in the B800 position in LH2a or free in solventsb, and the associated energy transfer yieldc. Energy transfer yields obtained from excitation-absorptance spectra and quenching are also included for comparison.
| B800 Pigment |
τLH2a (ps) |
τ solvent (ps)b |
ΦEET (τ)c |
ΦEET (exc)d |
ΦEET (Quench)e |
ΦEET Average |
|---|---|---|---|---|---|---|
| Chl a | 6.7 ± 0.7 (WT) 5.6 ± 0.4 (βR30F) 6.9 ± 0.5 (βR30L) |
6300 | >0.99 >0.99 >0.99 |
0.78 0.64 0.73 |
0.95 0.91 0.96 |
0.91 ± 0.12 0.85 ± 0.18 0.89 ± 0 0.15 |
| 3-Acetyl-Chl a | 5.1 ± 0.5 | 5600 | >0.99 | 0.88 | 0.89 | 0.92 ± 0.07 |
| Chl d | 3.5 ± 0.7 | 6500 | >0.99 | 0.81 | 0.93 | 0.91 ± 0.10 |
| Chl f | 2.7 ± 0.8 | >0.99 | 0.73 | n/df | 0.9 ± 0.2 | |
| BChl a | 0.5 ± 0.2 (WT) 0.8 ± 0.6 (βR30F) 0.6 ± 0.1 (βR30L) |
3000 | >0.99 >0.99 >0.99 |
1.03 0.97 0.94 |
n/df | 1.02 ± 0.02 0.99 ± 0.02 0.97 ± 0.04 |
| BChl b | ≤0.1g | 2400 | >0.99 | 1.05 | n/df | 1.03 ± 0.04 |
a
See Table S2 for component rates.
b
Average of lifetimes obtained in pyridine and toluene (error ± 10%). See Table S3.
c
Calculated using the formula ΦEET = 1 − τLH2/τsolvent.
d
Obtained from the ratio of the integrated (B)Chl Q band in the excitation vs. absorptance spectra.
e
Obtained by relative intensity of Chl a emission when bound to LH2 vs. free in solvent.
f
Not determined due to overlap of B800 pigment spectrum and that of B850 BChl a or limited sample.
g
Limited by the response of the instrument.