ISSN:
1573-5079
Keywords:
electron-proton transfer
;
photosynthetic bacterial reaction centre
;
step-scan Fourier transform infrared spectroscopy
;
ubiquinone
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract It is shown that step-scan Fourier transform infrared spectroscopy can be applied to resolve the QA −QB → QAQB − transition in Rhodobacter sphaeroides reaction centres with a 5 µs time resolution. In the mid-infrared region (1900 – 1200 cm−1), transient signals previously assigned to QA/B and QA/B − vibrations, respectively (Brudler et al. 1994; Brudler et al. 1995; Breton and Nabedryk 1996), can be resolved with this new technique. In addition, the three small positive bands in the spectral region of the carboxylic C=O stretching modes of acidic amino acid side chains are also resolved at 1730, 1719 and 1704 cm−1. A global fit analysis yields two exponentials with half-times of 150 µs and 1.2 ms in agreement with IR spectroscopic studies at single wavenumbers (Hienerwadel et al. 1995), in the UV/VIS and near IR (Tiede et al. 1996, Li et al. 1996). The establishement of the step-scan technique enables a new approach to elucidate the molecular mechanism of this transition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1006034322353
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