Resonance Raman studies of genetically modified reaction centers from Rhodobacter capsulatus.
Resonance Raman studies of genetically modified reaction centers from Rhodobacter capsulatus.
复制标题
荚膜红杆菌转基因反应中心的共振拉曼研究。
DOI：
10.1021/bi00488a031
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发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
Bocian,DF
中科院分区：
文献类型：
--
作者：
Peloquin,JM;Bylina,EJ;Youvan,DC;Bocian,DF
Leu.光谱是在30和200 K的温度下用各种激发波长获得的，跨越吸收光谱的UV、紫色和黄绿色区域。RR数据表明Rb来源的RCs中的细菌绿素的结构与Rb来源的RCs中的细菌绿素的结构相似。荚膜红细菌野生型的RC中的那些类似于来自球形红细菌野生型的RC中的那些。数据还表明，附近的主要电子受体（GluL 104-* Leu）和特殊对（HisM 20-* Leu）的氨基酸修饰扰乱只有那些细菌绿素色素附近的突变位点，并不影响RC中的其他色素的结构。在GluL 104-*· Leu突变体的情况下，BPhL的C9酮基的氢键的消除导致大环的某些骨架模式的RR带的频移。这允许将条带分配给单独的BPhL和BPhM色素。在HisM 200-*Leu突变体的情况下，其中特殊的一对由细菌叶绿素（BChl）-细菌脱镁叶绿素（BPh）异二聚体组成，而不是在野生型中结合的BChl 2单位，由于额外的BPh单位，确定了某些骨骼振动。这些模式的频率类似于BPhL和BPhM的类似振动，这表明在异源二聚体中的theBPh结构在任何可辨别的方式中并不罕见。为了Rb。capsulatus野生型和HisM 200-* Leu突变体，两个BPh之一的结构敏感的骨架模式的频率随着温度的变化，如以前观察到的类似的RR带的RC从Rb。sphaeroides [Pelofogin，J.M.，维奥莱特角一、Frank，HA，& Bocian，D. F.（1990）Biochemistry 29，4892-4898]。从GluL 104-* Leu突变体获得的RR数据证实了这种色素是BPhL。此外，对于来自GluL 104 - 1的RC中的BPhL的骨架模式的RR带，没有观察到温度依赖性。
Leu. The spectra were obtained with a variety of excitation wavelengths, spanning the UV, violet, and yellow-green regions of the absorption spectrum, and at temperatures of 30 and 200 K. The RR data indicate that thestructures of the bacteriochlorin pigments in RCs from Rb. capsulatus wild type are similar to those in RCs from Rhodobacter sphaeroides wild type. The data also show that the amino acid modifications near the primary electron acceptor (GluL104-* Leu) and special pair (HisM20-* Leu) perturb only those bacteriochlorin pigments near the site of the mutation and do not influence the structures of the other pigments in the RC. In the case of the GluL104-*· Leu mutant, elimination of the hydrogen bond to the C9 keto group of BPhL results in frequency shifts of RR bands of certain skeletal modes of the macrocycle. This allows the assignment of bands to the individual BPhL and BPhM pigments. In the case of the HisM200—*Leu mutant, in which thespecial pair is comprised of a bacteriochlorophyll (BChl)-bacteriopheophytin (BPh) heterodimer rather than the BChl2 unit bound in the wild type, certain skeletal vibrations due to the additional BPh unit are identified. The frequencies of these modes are similar to those of the analogous vibrations of BPhL and BPhM, which indicates that the structure of theBPh in the heterodimer is not unusual in any discernible way. For Rb. capsulatus wild type and the HisM200-* Leu mutant, the frequencies of the structure-sensitive skeletal modes of one of the two BPhs shift with temperature as has been previously observed for the analogous RR bands of RCs from Rb. sphaeroides [Peloquin, J. M., Violette, C. A., Frank, HA, & Bocian, D. F.(1990) Biochemistry 29, 4892-4898]. The RR data obtained for the GluL104—* Leu mutant confirm that this pigment is BPhL. In addition, no temperature dependence is observed for the RR bands of the skeletal modes of the BPhL in RCs from the GluL104-»