Rapid-flow resonance Raman spectroscopy of bacterial photosynthetic reaction centers.
Rapid-flow resonance Raman spectroscopy of bacterial photosynthetic reaction centers.
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细菌光合反应中心的快流共振拉曼光谱。
DOI：
10.1073/pnas.88.24.11207
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发表时间：
1991
影响因子：
11.1
通讯作者：
Mathies,RA
中科院分区：
文献类型：
--
作者：
Shreve,AP;Cherepy,NJ;Franzen,S;Boxer,SG;Mathies,RA
利用与最低能量、光化学活性电子吸收共振的激发波长（810-910 nm），获得了球形红细菌R-26突变体细菌光合反应中心的快流共振拉曼振动光谱。位移激发拉曼差谱技术用于在大荧光背景下识别真正的拉曼散射带。对未处理的反应中心和用氧化剂K_3Fe（CN）_6处理的反应中心的光谱进行了比较，结果表明，特殊的对得到了共振增强。相对较强的拉曼散射被观察到的特殊对振动频率为36，94，127，202，730，和898 cm-1;其他模式被观察到在71，337，和685 cm-1。定性拉曼激发配置文件的一些强模式，并观察到共振增强发生在整个近红外吸收带的特殊对。这些拉曼数据确定了哪些振动与特殊对中的光吸收耦合，从而探测了电子激发后发生的核运动。解释以前的空穴燃烧实验和激发态动力学和反应中心的光化学的影响进行了讨论。
Rapid-flow resonance Raman vibrational spectra of bacterial photosynthetic reaction centers from the R-26 mutant of Rhodobacter sphaeroides have been obtained by using excitation wavelengths (810-910 nm) resonant with the lowest energy, photochemically active electronic absorption. The technique of shifted excitation Raman difference spectroscopy is used to identify genuine Raman scattering bands in the presence of a large fluorescence background. The comparison of spectra obtained from untreated reaction centers and from reaction centers treated with the oxidant K3Fe(CN)6 demonstrates that resonance enhancement is obtained from the special pair. Relatively strong Raman scattering is observed for special pair vibrations with frequencies of 36, 94, 127, 202, 730, and 898 cm-1; other modes are observed at 71, 337, and 685 cm-1. Qualitative Raman excitation profiles are reported for some of the strong modes, and resonance enhancement is observed to occur throughout the near-IR absorption band of the special pair. These Raman data determine which vibrations are coupled to the optical absorption in the special pair and, thus, probe the nuclear motion that occurs after electronic excitation. Implications for the interpretation of previous hole-burning experiments and for the excited-state dynamics and photochemistry of reaction centers are discussed.