Lipid enrichment of thylakoid membranes. I. Using soybean phospholipids |
| |
Authors: | P.A. Millner J.P. Grouzis D.J. Chapman J. Barber |
| |
Affiliation: | ARC Photosynthesis Research Group, Department of Pure and Applied Biology, Imperial College, London SW7 2BB U.K. |
| |
Abstract: | (1) Using asolectin (mixed soybean phospholipids) liposomes, extra lipid, with or without additional plastoquinone, has been introduced into isolated thylakoid membranes of pea chloroplasts. (2) Evidence for this lipid enrichment was obtained from freeze-fracture which indicated that a decrease in the numbers of EF and PF particles per unit area of membrane occurred with increasing lipid incorporation. The decrease was not due to loss of integral membrane polypeptides as judged by assay of cytochrome present or SDS-polyacrylamide gel electrophoresis of lipid-enriched membrane fractions. Moreover, the enrichment procedure did not lead to extraction of low molecular weight lipophilic membrane components or of thylakoid membrane lipids. (3) The introduction of phospholipids into the membrane affected steady-state electron transport. Inhibition of electron transport was observed when either water (Photosystem (PS) II + PS I) or duroquinol (PS I) was used as electron donor with methyl viologen as electron acceptor, and the degree of inhibition increased with higher enrichment levels. Introduction of exogenous plastoquinone with the additional lipid had little effect on whole-chain electron transport, but caused an increase in the 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB)-sensitive rate of PS I electron transport. The inhibition was also detected by flash-induced oxidation-reduction changes of cytochrome f. |
| |
Keywords: | Lipid enrichment Liposome Freeze - fracture (Pea thylakoid) Chl chlorophyll Hepes PS photosystem DCMU 3-(3,4-dichlorophenyl)-1,1 dimethylurea DBMIB PQ plastoquinone Mes 4-morpholineethanesulphonic acid |
本文献已被 ScienceDirect 等数据库收录! |
|