Effect of carotenoids and monogalactosyl diglyceride on bacteriochlorophyll c aggregates in aqueous buffer: implications for the self-assembly of chlorosomes
Language English Country United States Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
15623345
DOI
10.1562/0031-8655(2004)080<0572:eocamd>2.0.co;2
PII: 2004-07-14-RA-232R
Knihovny.cz E-resources
- MeSH
- Bacterial Proteins chemistry MeSH
- Bacteriochlorophylls chemistry MeSH
- Chlorobium chemistry MeSH
- Galactolipids chemistry pharmacology MeSH
- Carotenoids chemistry pharmacology MeSH
- Buffers MeSH
- Solubility MeSH
- Spectrum Analysis MeSH
- Protein Binding drug effects MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- bacteriochlorophyll c MeSH Browser
- Bacterial Proteins MeSH
- Bacteriochlorophylls MeSH
- Galactolipids MeSH
- Carotenoids MeSH
- Buffers MeSH
Aggregation of bacteriochlorophyll (BChl) c from chlorosomes, the main light-harvesting complex of green bacteria, has been studied in aqueous buffer. Unlike other chlorophyll-like molecules, BChl c is rather soluble in aqueous buffer, forming dimers. When BChl c is mixed with carotenoids (Car), the BChl c Qy transition is further redshifted, in respect to that of monomers and dimers. The results suggest that Car are incorporated in the aggregates and induce further aggregation of BChl c. The redshift of the BChl c Qy band is proportional to the Car concentration. In contrast, the mixture of bacteriochlorophyllide (BChlide) c, which lacks the nonpolar esterifying alcohol, does not form aggregates with Car in aqueous buffer or nonpolar solvents. Instead, the position of the BChlide c Qy transition remains unshifted in respect to that of the monomeric molecule, and Car precipitates with the course of time in aqueous buffer. Similar effects on both BChl c and BChlide c are also observed when monogalactosyl diglyceride (MGDG), which forms the monolayer envelope of chlorosomes, is used instead of (or together with) Car. The results show that the hydrophobic interactions of the BChl c esterifying alcohols with themselves and the nonpolar carbon skeleton of Car, or the fatty acid tails of MGDG, are essential driving forces for BChl aggregation in chlorosomes.
References provided by Crossref.org
Superradiance of bacteriochlorophyll c aggregates in chlorosomes of green photosynthetic bacteria
Low-temperature spectroscopy of bacteriochlorophyll c aggregates
Structural and functional roles of carotenoids in chlorosomes
Structure of chlorosomes from the green filamentous bacterium Chloroflexus aurantiacus
Effect of quinones on formation and properties of bacteriochlorophyll c aggregates
