Hole-Burning and Absorption Studies of the LH1 Antenna Complex of Purple Bacteria: Effects of Pressure and Temperature
| Autor: | Gerald J. Small, H.-M. Wu, Ryszard Jankowiak, R. J. Cogdell, M. Ratsep |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Materials science
biology Exciton Analytical chemistry biology.organism_classification Purple bacteria Spectral line Surfaces Coatings and Films Rhodobacter sphaeroides chemistry.chemical_compound chemistry Absorption band Chlorophyll Materials Chemistry Molecule Physical and Theoretical Chemistry Absorption (electromagnetic radiation) |
| Zdroj: | The Journal of Physical Chemistry B. 102:4023-4034 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp980420z |
| Popis: | Spectral hole-burning and absorption spectroscopies were combined with pressure and temperature in studies of the light harvesting 1 (LH1 or B875) antenna complex of wild-type (WT) chromatophores and an LH1-only mutant of Rhodobacter sphaeroides. Zero-phonon hole (ZPH) action spectra lead to values of 120 (WT) and 140 cm-1 (mutant) for the separation (ΔE) between the lowest energy exciton level of A symmetry, B896, and the adjacent, strongly absorbing E1 level of the C16 ring of 32 bacteriochlorophyll a molecules. The E1 level is responsible for most of the B875 band's absorption intensity. Values for the inhomogeneous broadening of the relatively weak B896 absorption band are given. High-pressure hole-burning data for the B896 band yielded a very large linear pressure shifting of −0.67 cm-1/MPa, about 10% higher than the shift rate for the B875 absorption band. These shifts are about a factor of 7 times higher than those of weakly coupled chlorophyll molecules in protein complexes and isolated chromophor... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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