Cladera J, Villaverde J, Hartog A F, Padrós E, Berden J A, Rigaud J L, Duñach M
Dept. Bioquimica i Biologia Molecular, Fac. Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain.
FEBS Lett. 1995 Sep 4;371(2):115-8. doi: 10.1016/0014-5793(95)00865-7.
We have studied the secondary structure of mitochondrial F1 using infrared spectroscopy. Our results show that in the absence of added nucleotides this complex contains similar percentages of alpha-helices, beta-structures and reverse turns (30%, 28% and 31%, respectively). The influence of ADP and ATP on the different types of secondary structure was determined; when all the nucleotide-binding sites were occupied, small but reproducible changes were observed, corresponding to a decrease in beta-structure and an increase in alpha-helix and reverse turns. The effect of nucleotide binding on the thermal stability of F1 was also studied; the thermal denaturation temperature, 55 degrees C, was increased by 11 degrees C and 7 degrees C by ATP and ADP, respectively. These results indicate that nucleotide binding affects the secondary structure of F1, stabilizing the complex.
我们利用红外光谱研究了线粒体F1的二级结构。我们的结果表明，在未添加核苷酸的情况下，该复合物中α-螺旋、β-结构和反向转角的比例相似（分别为30%、28%和31%）。确定了ADP和ATP对不同类型二级结构的影响；当所有核苷酸结合位点被占据时，观察到了微小但可重复的变化，对应于β-结构的减少以及α-螺旋和反向转角的增加。还研究了核苷酸结合对F1热稳定性的影响；热变性温度55℃，ATP和ADP分别使其升高了11℃和7℃。这些结果表明核苷酸结合会影响F1的二级结构，使该复合物更加稳定。
