Low-temperature femotosecond-resolution transient absorption spectroscopy of large-scale symmetry mutants of bacterial reaction centers
- Arizona State Univ., Tempe, AZ (United States); and others
Reaction centers isolated from three large-scale symmetry mutants, sym0, sym2-1, and sym5-2 described in the previous article of this issue have been investigated by low-temperature ground state and femotosecond-resolution transient absorption spectroscopy. All three of these large-scale symmetry mutants undergo electron transfer at 20 K. The mutants sym0 and sym5-2 have yields and dominant rates of charge separation comparable to wild type. However, the sym2-1 mutant shows a roughly 35% quantum yield at this temperature, and the major kinetic component of the initial electron transfer is slower than wild type by nearly a factor of 100. The sym0 mutant showed substantial changes in the monomer bacteriochlorophyll ground state and transient spectra, and both sym0 and sym2-1 showed changes in the bacteriophenophytin ground state and transient spectra. In particular, sym2-1 shows a small absorbance decrease in the region of the Q{sub x} band of the B side bacteriophenophytin which could be attributed to 10%-20% electron transfer along the B pathway. 54 refs., 5 figs., 1 tab.
- DOE Contract Number:
- FG05-88ER75443; FG05-87ER75361
- OSTI ID:
- 472122
- Journal Information:
- Biochemistry (Eaton), Vol. 35, Issue 10; Other Information: PBD: 12 Mar 1996
- Country of Publication:
- United States
- Language:
- English
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