Institute of Biochemistry, Odense University, Campusvej 55, DK-5230, Odense M, Denmark.
Photosynth Res. 1990 Jul;25(1):25-37. doi: 10.1007/BF00051733.
Bacteriochlorophyll c in vivo is a mixture of at least 5 homologs, all of which form aggregates in CH2Cl2, CHCl3 and CCl4. Three homologs exist mainly in the 2-R-(1-hydroxyethyl) configuration, whereas the other two homologs, 4-isobutyl-5-ethyl and 4-isobutyl-5-methyl farnesyl bacteriochlorophyll c, exist mainly in the 2-S-(1-hydroxyethyl) configuration (Smith KM, Craig GW, Kehres LA and Pfennig N (1983) J. Chromatograph. 281: 209-223). In CCl4 the S-homologs form an aggregate of 2-3 molecules whose absorption (747 nm maximum) and circular dichroism spectra resemble those of the chlorosome. In CH2Cl2, CHCl3 and CCl4 the 4-n-propyl homolog (R-configuration) forms dimers absorbing at ca. 680 nm and higher aggregates absorbing at 705-710 nm. In CCl4 the dimerization constant is approx. 10 µM(-1) (1000 times that for chlorophyll a). The difference between the types of aggregates formed by the 4-n-propyl and 4-isobutyl homologs is attributed to the difference between the R- and S-configurations of the 2-(1-hydroxyethyl) groups in each chlorophyll.
细菌叶绿素 c 在体内是至少 5 种同系物的混合物，所有这些同系物在 CH2Cl2、CHCl3 和 CCl4 中都形成聚集体。三种同系物主要以 2-R-(1-羟乙基）构型存在，而另外两种同系物，4-异丁基-5-乙基和 4-异丁基-5-甲基法呢基细菌叶绿素 c，主要以 2-S-(1-羟乙基）构型存在（Smith KM、Craig GW、Kehres LA 和 Pfennig N（1983）J. Chromatograph. 281: 209-223）。在 CCl4 中，S-同系物形成 2-3 个分子的聚集体，其吸收（最大 747nm）和圆二色性光谱与类囊体相似。在 CH2Cl2、CHCl3 和 CCl4 中，4-正丙基同系物（R-构型）形成吸收约 680nm 的二聚体和吸收 705-710nm 的更高聚集体。在 CCl4 中，二聚常数约为 10µM-1（是叶绿素 a 的 1000 倍）。4-正丙基和 4-异丁基同系物形成的聚集体类型的差异归因于每个叶绿素中 2-(1-羟乙基）基团的 R-和 S-构型的差异。
