Modified reaction centers from Rhodobacter sphaeroides R26

Struck, A. and Scheer, Hugo (1990): Modified reaction centers from Rhodobacter sphaeroides R26. Exchange of monomeric bacteriochlorophyll with 132-hydroxy-bacteriochlorophyll. In: FEBS Letters, Vol. 261, No. 2: pp. 385-388

Abstract

Incubation of photosynthetic reaction centers from Rhodobacter sphaeroides R26 with exogenous 132-OH-bacteriochlorophyll ap or aGG according to Scheer et al. (1987) results in the exchange of endogenous bacteriochlorophyll ap. The exchange amounts to less-than-or-equals, slant 50% according to HPLC analysis, corresponding to a complete replacement of the ‘monomeric’ bacteriochlorophylls, bm and bl, by exogenous pigment. The absorption spectra show small, but distinct changes in the Qx-region of the bacteriochlorophylls, and bleaching of the modified reaction centers is retained. The corresponding binding sites must be accessible from the exterior, and allow for the introduction of a polar residue at C-132. This is supported by the observation of side reactions of the endogenous ‘monomeric’ bacteriochlorophylls within the reaction center pigments, e.g. epimerization and hydroxylation at C-132.

• Item Type: Article
• Keywords: Photosynthesis; Reaction center; Pigment modification; Pigment exchange; Chlorophyll; Bacteriochlorophyll a; Bacteriochlorophyll a'; 132-Hydroxy-bacteriochlorophyll a; Chromatography; Esterifying alcohol; Epimerization; Oxidation; (Rhodobacter sphaeroides)
• Collections: Biology
• Subjects: 500 Science > 570 Life sciences; biology