Institut für Molekularbiologie und Biophysik, ETH-Hönggerberg, 8093, Zürich, Switzerland.
Photosynth Res. 1994 Jul;41(1):165-73. doi: 10.1007/BF02184157.
The circular dichroism (CD) spectrum of isolated chlorosomes fromChloroflexus aurantiacus showed a conservative, S-shaped signal with a negative maximum at 723 nm, a positive maximum at 750 nm and a zero-crossing at 740 nm. Proteolytic treatment of chlorosomes with trypsin at 37°C did not change the CD signal or the absorption spectrum in contrast to treatment with proteinase K, where a twofold increase in rotational strength and a slight decrease of the absorption band at 740 nm were observed. Treatment with saturating 1-hexanol concentrations resulted in a blue shift of the absorption band at 740 nm as well as in changes of the CD spectrum. These changes reversed when the sample was diluted to half the saturating 1-hexanol concentration. In contrast to that, we observed an irreversible formation of a giant CD signal using the combination of 1-hexanol and proteinase K treatment. Electron micrographs of chlorosomes treated with both 1-hexanol and proteinase K showed large aggregates of multiple chlorosome size. By comparison of proteinase K induced effects with trypsin effects it appeared that the 5.7 kDa polypeptide has a structural role in the organisation of BChlc in the chlorosome.
从黄柄杆菌（Chloroflexus aurantiacus）中分离出的菌绿体的圆二色性（CD）光谱显示出保守的 S 形信号，其负极大值在 723nm，正极大值在 750nm，零交叉在 740nm。与蛋白酶 K 处理相比，用胰蛋白酶在 37°C 处理菌绿体不会改变 CD 信号或吸收光谱，而在蛋白酶 K 处理中，旋转强度增加了一倍，740nm 处的吸收带略有下降。用饱和 1-己醇浓度处理会导致 740nm 处的吸收带蓝移以及 CD 光谱的变化。当样品稀释至饱和 1-己醇浓度的一半时，这些变化会逆转。相比之下，我们观察到使用 1-己醇和蛋白酶 K 处理的组合会产生不可逆的巨大 CD 信号。用 1-己醇和蛋白酶 K 处理的菌绿体的电子显微镜照片显示出多个菌绿体大小的大聚集体。通过比较蛋白酶 K 诱导的效应与胰蛋白酶效应，似乎 5.7kDa 多肽在菌绿体中 BChlc 的组织中具有结构作用。
