Bacteriochlorophyll-protein interaction in the light-harvesting complex B800-850 from Rhodobacter sulfidophilus: A Fourier-transform Raman spectroscopic investigation

W. Mäntele, J. Sawatzki, M. Doi, N. Gad'on, G. Drews

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

Near-infrared excited Fourier-transform Raman spectra have been obtained from different spectral forms of Rhodobacter sulfidophilus light-harvesting II complexes. This complex, when isolated in lauryldimethylamine oxide, exists in a 805-828 nm form, which can be reversibly converted to the native 805-851 nm form upon addition of salt. The FT-Raman spectra predominantly show contributions of the carotenoid in the light-harvesting complex, with small but significant contributions of the bacteriochlorophylls excited in preresonance in the Qy transition. One strongly and one weakly interacting 2a acetyl C=O group as well as one moderately strong interacting and one non-interacting 9-keto C=O carbonyl modes of the bacteriochlorophylls can be discerned for the 805-828 nm form. Changes of relative band intensities caused by different resonance conditions for the different spectral forms lead to an assignment of the strongly interacting 2a acetyl C=O and the moderately strong interacting 9 keto C=O to bacteriochlorophylls organized in the 828 pigment moiety. Shifts of these bands to higher frequencies upon the salt-induced transition indicate a perturbation of the pigment-protein interaction, probably caused by a local protein conformational change.

Original languageEnglish
Pages (from-to)367-372
Number of pages6
JournalBBA - Bioenergetics
Volume1057
Issue number3
DOIs
Publication statusPublished - May 6 1991

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Cell Biology

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