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Protective effect of histidine against pigment photobleaching in Photosystem I particles♣

M. VELITCHKOVA1, S. ABAROVA2, D. LAZAROVA1, K. STOITCHKOVA2, D. STANOEVA1, A. ANDREEVA2,*

Affiliation

  1. Institute of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev str. bl.21, 1113 Sofia, Bulgaria
  2. Sofia University, Faculty of Physics, Department of Condensed Matter Physics, 5, J. Bourchier blvd., 1164 Sofia, Bulgaria

Abstract

Photosystem I (PSI) is a supercomplex of a reaction centre and light-harvesting complexes. Photosystem I particles isolated from spinach leaves were studied by means of absorbance, 77 K fluorescence, and resonance Raman spectroscopy. During prolonged exposure to high-light intensities, various pigments in Photosystem I exhibited different susceptibilities to photodestruction. This work presents preliminary investigations on the effect of histidine on the photobleaching of pigments in isolated particles of photosystem I. Resonance Raman spectroscopy allowed us to obtain direct information about the effect of histidine on the photobleaching of the lutein molecules, upon excitation with a 514.5 nm laser line. Our results showed that histidine reduces the photobleaching of antenna pigments and especially luteins and the most long-wavelength absorbing chlorophylls located in the PSI antenna complex..

Keywords

Pigments, Raman spectroscopy, Photobleaching, Photosystem I.

Submitted at: Nov. 5, 2008
Accepted at: Sept. 9, 2009

Citation

M. VELITCHKOVA, S. ABAROVA, D. LAZAROVA, K. STOITCHKOVA, D. STANOEVA, A. ANDREEVA, Protective effect of histidine against pigment photobleaching in Photosystem I particles♣, Journal of Optoelectronics and Advanced Materials Vol. 11, Iss. 9, pp. 1230-1233 (2009)