Burkovski A, Lill H, Engelbrecht S
Universität Osnabrück, Germany.
Biochim Biophys Acta. 1994 Jul 29;1186(3):243-6. doi: 10.1016/0005-2728(94)90184-8.
ATP-synthesizing F0F1-ATPases are complex enzymes consisting of at least eight different subunits. These subunits are conserved during evolution to a very variable degree ranging in pairwise comparison between, for example, Escherichia coli and spinach chloroplast from 20% to 66% identical residues. It was surprising to find that some of the less well conserved subunits like delta and epsilon could replace their E. coli counterparts, whereas the highly conserved beta subunit, which carries the active site, in the E. coli enzyme could not be substituted by spinach chloroplast beta (Lill et al. (1993) Biochim. Biophys. Acta 1144, 278-284). We constructed a chimeric F1-beta subunit consisting of spinach beta in which the 96 N-terminal amino acids were replaced by the respective residue sequence from E. coli beta. Whereas spinach beta did not complement E. coli uncD mutant strains, the chimeric beta subunit restored growth under conditions of oxidative phosphorylation.
合成ATP的F0F1 - ATP酶是由至少八个不同亚基组成的复合酶。这些亚基在进化过程中保守程度差异很大，例如在大肠杆菌和菠菜叶绿体之间进行两两比较时，相同残基的比例在20%至66%之间。令人惊讶的是，一些保守程度较低的亚基，如δ和ε亚基，可以替代其在大肠杆菌中的对应亚基，而在大肠杆菌酶中携带活性位点的高度保守的β亚基却不能被菠菜叶绿体的β亚基替代（Lill等人，（1993年）《生物化学与生物物理学报》1144卷，278 - 284页）。我们构建了一个嵌合的F1 - β亚基，它由菠菜β亚基组成，其中96个N端氨基酸被大肠杆菌β亚基的相应残基序列所取代。虽然菠菜β亚基不能互补大肠杆菌uncD突变株，但嵌合的β亚基在氧化磷酸化条件下恢复了生长。
