Guo Y J, Zhang Y, Liu Y X, Lin Z H
Institute of Biophysics, Academia Sinica, Beijing, China.
Biochim Biophys Acta. 1987 Oct 29;894(1):11-5. doi: 10.1016/0005-2728(87)90207-6.
The conformations of the H+-ATPase complex and F1-ATPase in low concentrations of methanol, ethanol, n-propanol, iso-propanol and t-butanol were studied by circular dichroism. For F1-ATPase, all but methanol first increased and then decreased the circular dichroism magnitude of helical bands as the alcohol concentration was increased. With ethanol, n-propanol, iso-propanol and t-butanol, the alpha-helix content reached a maximum at about 5% alcohol and began to decrease at 10%. The content of beta-sheet showed the opposite effect, reaching a minimum at 5% and increasing slightly at higher concentrations. None of the alcohols studied had a significant effect on the conformation of the H+-ATPase complex. This difference implies that the alcohols had a greater effect on free F1-ATPase than on the membrane-bound F1-ATPase. The hydrophobic protein F0 and the membrane lipids in the H+-ATPase complex may stabilize and protect F1 from the effects of the alcohols.
通过圆二色性研究了低浓度甲醇、乙醇、正丙醇、异丙醇和叔丁醇中H⁺-ATP酶复合物和F1-ATP酶的构象。对于F1-ATP酶，随着醇浓度的增加，除甲醇外，其他醇类首先增加然后降低螺旋带的圆二色性强度。对于乙醇、正丙醇、异丙醇和叔丁醇，α-螺旋含量在约5%的醇浓度时达到最大值，并在10%时开始下降。β-折叠的含量表现出相反的效果，在5%时达到最小值，并在较高浓度时略有增加。所研究的醇类对H⁺-ATP酶复合物的构象均无显著影响。这种差异表明，醇类对游离F1-ATP酶的影响比对膜结合F1-ATP酶的影响更大。H⁺-ATP酶复合物中的疏水蛋白F0和膜脂可能会稳定并保护F1免受醇类的影响。
