Gast P, Hemelrijk P W, Van Gorkom H J, Hoff A J
Department of Biophysics, Leiden University, The Netherlands.
Eur J Biochem. 1996 Aug 1;239(3):805-9. doi: 10.1111/j.1432-1033.1996.0805u.x.
Detergent-free reaction centers from Rhodobacter sphaeroides R26 were used to study the solubilization of reaction centers in various detergents and their effects on reaction center photochemistry. 500 +/- 100 n-octyl-beta-D-glucopyranoside or 51 +/- 5 Triton X-100 molecules were associated with one reaction center. For N.N-alkylamine N-oxide detergents with chain lengths in the range from 8-13 carbon atoms, the number of detergent molecules associated with the reaction centers increased with decreasing chain length. The amount of detergent molecules associated with the reaction centers decreased almost tenfold if the pH was increased from pH 6 to pH 10. The addition of 5% 1,2,3-heptanetriol to various detergents lowered the detergent/reaction center ratio by a factor of two compared to that for the pure detergent. The detergent concentration at which solubilization of the reaction center occurs was close to the critical micelle concentration for all detergents studied. The absorption band at 865 nm of the primary donor in the reaction center shifts to 846 nm when detergent was removed from the reaction center; upon resolubilization with various detergents, this band shifts back to 865 nm. In 80-90% of the detergent-free reaction centers, the secondary electron transfer from QA to QB was inhibited: this electron transfer was restored after re-addition of detergent.
来自球形红细菌R26的无洗涤剂反应中心被用于研究反应中心在各种洗涤剂中的溶解情况及其对反应中心光化学的影响。500±100个正辛基-β-D-吡喃葡萄糖苷分子或51±5个Triton X-100分子与一个反应中心相关联。对于碳链长度在8至13个碳原子范围内的N,N-烷基胺N-氧化物洗涤剂，与反应中心相关联的洗涤剂分子数量随着链长的缩短而增加。如果pH值从pH 6增加到pH 10，与反应中心相关联的洗涤剂分子数量几乎减少了十倍。与纯洗涤剂相比，向各种洗涤剂中添加5%的1,2,3-庚三醇可使洗涤剂/反应中心比例降低两倍。对于所有研究的洗涤剂，反应中心发生溶解时的洗涤剂浓度接近临界胶束浓度。当从反应中心去除洗涤剂时，反应中心中初级供体在865 nm处的吸收带移至84６nm；用各种洗涤剂重新溶解后，该吸收带又移回865 nm。在80%至90%的无洗涤剂反应中心中，从QA到QB的二次电子转移受到抑制：重新添加洗涤剂后，这种电子转移得以恢复。
