Temperature and cryoprotectant influence secondary quinone binding position in bacterial reaction centers.
Temperature and cryoprotectant influence secondary quinone binding position in bacterial reaction centers.
复制标题
温度和冷冻保护剂影响细菌反应中心的仲醌结合位置。
DOI：
10.1016/j.febslet.2004.06.042
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发表时间：
2004
期刊：
影响因子：
3.5
通讯作者：
Schiffer,Marianne
中科院分区：
文献类型：
--
作者：
Pokkuluri,PRaj;Laible,PhilipD;Crawford,AdamE;Mayfield,JoyF;Yousef,MohammedA;Ginell,StephanL;Hanson,DeborahK;Schiffer,Marianne
We have determined the first de novo position of the secondary quinone QBin theRhodobacter sphaeroidesreaction center (RC) using phases derived by the single wavelength anomalous dispersion method from crystals with selenomethionine substitution. We found that in frozen RC crystals, QBoccupies primarily the proximal binding site. In contrast, our room temperature structure showed that QBis largely in the distal position. Both data sets were collected in dark‐adapted conditions. We estimate that the occupancy of the QBsite is 80% with a proximal: distal ratio of 4:1 in frozen RC crystals. We could not separate the effect of freezing from the effect of the cryoprotectants ethylene glycol or glycerol. These results could have far‐reaching implications in structure/function studies of electron transfer in the acceptor quinone complex because the above are the most commonly used cryoprotectants in spectroscopic experiments.
