Engelbrecht S, Reed J, Penin F, Gautheron D C, Junge W
Biophysik, Fachbereich Biologie/Chemie, Universität Osnabrück.
Z Naturforsch C J Biosci. 1991 Sep-Oct;46(9-10):759-64. doi: 10.1515/znc-1991-9-1007.
CD spectra have been recorded with subunit delta from chloroplast CF0CF1 and with OSCP from mitochondrial MF0MF1. These subunits are supposed to act similarly at the interface between proton transport through the F0-portion and ATP-synthesis in the F1-portion of their respective F0F1-ATPase. Evaluation of the data for both proteins revealed a very high alpha-helix content of approximately 85% and practically no beta-sheets. Despite their low homology on the primary structure level (23% identity) and their different electrostatic properties (pI-values differ by 3 units), spinach delta and porcine OSCP are indistinguishable with respect to their secondary structure as measured by CD. Prediction and analysis of consensual alpha-helices even in poorly conserved regions indicate a high degree of structural similarity between chloroplast delta and OSCP. In view of the topology and function of delta and OSCP in intact F0F1 these findings are interpreted to indicate the dominance of secondary and tertiary structure over the primary structure in their supposed function between proton flow and ATP-synthesis.
已使用来自叶绿体CF0CF1的δ亚基和来自线粒体MF0MF1的OSCP记录了圆二色光谱。这些亚基在各自的F0F1 - ATP酶中，在通过F0部分的质子运输与F1部分的ATP合成之间的界面处，被认为具有相似的作用。对这两种蛋白质的数据评估显示，它们的α - 螺旋含量非常高，约为85%，几乎没有β - 折叠。尽管菠菜δ亚基和猪OSCP在一级结构水平上同源性较低（同一性为23%），且它们的静电性质不同（pI值相差3个单位），但通过圆二色光谱测量，它们的二级结构无法区分。即使在保守性较差的区域，对共有α - 螺旋的预测和分析也表明叶绿体δ亚基和OSCP之间存在高度的结构相似性。鉴于δ亚基和OSCP在完整F0F1中的拓扑结构和功能，这些发现被解释为表明在质子流和ATP合成之间的假定功能中，二级和三级结构比一级结构更具主导性。
