Protein/Lipid Interaction in the Bacterial Photosynthetic Reaction Center: Phosphatidylcholine and Phosphatidylglycerol Modify the Free Energy Levels of the Quinones
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- 作者：Lá ; szló ; Nagy ; Francesco Milano ; Má ; rta Dorogi ; Angela Agostiano ; Gá ; bor Laczkó ; Korné ; lia Szebé ; nyi ; Gyö ; rgy Vá ; ró ; Massimo Trotta ; and P&e
- 刊名：Biochemistry
- 出版年：2004
- 出版时间：October 12, 2004
- 年：2004
- 卷：43
- 期：40
- 页码：12913 - 12923
- 全文大小：182K
- 年卷期：v.43,no.40(October 12, 2004)
- ISSN：1520-4995
文摘
The role of characteristic phospholipids of native membranes, phosphatidylcholine (PC),phosphatidylglycerol (PG), and cardiolipin (CL), was studied in the energetics of the acceptor quinoneside in photosynthetic reaction centers of Rhodobacter sphaeroides. The rates of the first, kAB(1), and thesecond, kAB(2), electron transfer and that of the charge recombination, kBP, the free energy levels of QA-QBand QAQB- states, and the changes of charge compensating protein relaxation were determined in RCsincorporated into artificial lipid bilayer membranes. In RCs embedded in the PC vesicle, kAB(1) and kAB(2)increased (from 3100 to 4100 s-1 and from 740 to 3300 s-1, respectively) and kBP decreased (from 0.77to 0.39 s-1) compared to those measured in detergent at pH 7. In PG, kAB(1) and kBP decreased (to valuesof 710 and 0.26 s-1, respectively), while kAB(2) increased to 1506 s-1 at pH 7. The free energy betweenthe QA-QB and QAQB- states decreased in PC and PG (
G
QA-QB
QAQB- = -76.9 and -88.5 meV,respectively) compared to that measured in detergent (-61.8 meV). The changes of the QA/QA- redoxpotential measured by delayed luminescence showed (1) a differential effect of lipids whether RCincorporated in micelles or vesicles, (2) an altered binding interaction between anionic lipids and RC, (3)a direct influence of PC and PG on the free energy levels of the primary and secondary quinones probablythrough the intraprotein hydrogen-bonding network, and (4) a larger increase of the QA/QA- free energyin PG than in PC both in detergent micelles and in single-component vesicles. On the basis of recentstructural data, implications of the binding properties of phospholipids to RC and possible interactionsbetween lipids and electron transfer components will be discussed.
GQA-QBQAQB- = -76.9 and -88.5 meV,respectively) compared to that measured in detergent (-61.8 meV). The changes of the QA/QA- redoxpotential measured by delayed luminescence showed (1) a differential effect of lipids whether RCincorporated in micelles or vesicles, (2) an altered binding interaction between anionic lipids and RC, (3)a direct influence of PC and PG on the free energy levels of the primary and secondary quinones probablythrough the intraprotein hydrogen-bonding network, and (4) a larger increase of the QA/QA- free energyin PG than in PC both in detergent micelles and in single-component vesicles. On the basis of recentstructural data, implications of the binding properties of phospholipids to RC and possible interactionsbetween lipids and electron transfer components will be discussed.