Distribution and self-organization of photosynthetic pigments in micelles: Implication for the assembly of light-harvesting complexes and reaction centers in the photosynthetic membrane
- Weizmann Institute of Science, Rehovot (Israel)
The addition of bacteriochlorophylls and bacteriopheophytins to formamide/water, 3:1 (vol/vol), (or water) containing small spherical micelles of Triton X-100 leads to the reorganization of the detergent into micelles that consist of 5,000-40,000 amphiphilic molecules. The pigment distribution within the micelles was determined by modified Poisson statistics taking into consideration the various sizes of micelles. Pigment dimerization occurred in micelles with more than a single occupant and was driven by a free-energy change of {minus}4.5 kcal/mol for bacteriochlorophyll a in formamide/water, {minus}7.6 kcal/mol for bacteriopheophytin a in formamide/water, and {minus}6.6 kcal/mol for bacteriopheophytin a in water. These values correspond to the room temperature equilibrium constants 2.2 {times} 10{sup 3} M{sup {minus}1}, 3.9 {times} 10{sup 5} M{sup {minus}1}, and 7.5 {times} 10{sup 4} M{sup {minus}1}, respectively. The incorporation of bacteriochlorophylls with attached small formamide polymers and the subsequent dimerization of these pigments in the lipid phase provide a model for studying the synergetic organization of polypeptides and bacteriochlorophyll clusters in the photosynthetic membrane.
- OSTI ID:
- 6265749
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 87:14; ISSN 0027-8424; ISSN PNASA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
ABSORPTION SPECTRA
AMIDES
BIOSYNTHESIS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHLOROPHYLL
DISTRIBUTION
FORMAMIDE
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MEMBRANES
MICELLAR SYSTEMS
MOLECULAR STRUCTURE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDES
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC BACTERIA
PHOTOSYNTHETIC MEMBRANES
PHOTOSYNTHETIC REACTION CENTERS
PHYTOCHROMES
PIGMENTS
POLYPEPTIDES
PORPHYRINS
PROTEINS
SPECTRA
SUBCELLULAR DISTRIBUTION
SYNTHESIS