DOPE、DOPC对重组去脂肌质网Ca^(2+)-ATPase活力和构象的影响  

EFFECT OF DOPE, DOPC ON THE ACTIVITY ANDCONFORMATION OF SR Ca^(2+)-ATPase

作　　者：李佳[1] 张旭家[1] 杨福愉[1] 

机构地区：[1]中国科学院生物物理研究所生物大分子国家重点实验室,北京100101

出　　处：《生物物理学报》1999年第4期631-639,共9页Acta Biophysica Sinica

摘　　要：经磷脂酶Ａ２ 去脂的肌质网Ｃａ２ ＋ － ＡＴＰａｓｅ 重组于不同比例的二油酰磷脂酰胆碱（Ｄｉｏｌｅｏｙｌｐｈｏｐｈａｔｉｄｙｌｃｈｏｌｉｎｅ，ＤＯＰＣ） 和二油酰磷脂酰乙醇胺（Ｄｉｏｌｅｏｙｌｐｈｏｐｈａｔｉｄｙｌｅｔｈａｎｏｌａｍｉｎｅ，ＤＯＰＥ） 形成脂酶体，研究了不同磷脂环境中Ｃａ２ ＋ － ＡＴＰａｓｅ 的ＡＴＰ 水解和Ｃａ２ ＋ 转运活力。结果表明，ＤＯＰＣ 和ＤＯＰＥ 分别有利于ＡＴＰ 水解和Ｃａ２ ＋ 的转运，ＤＯＰＥ 可以增强Ｃａ２ ＋ － ＡＴＰａｓｅ 的ＡＴＰ水解和Ｃａ２ ＋ 转运之间的偶联效率。利用内源荧光、荧光淬灭及Ｆｏｒｓｔｅｒ 能量转移原理测定Ｃａ２ ＋ －ＡＴＰａｓｅ 相应的构象变化， 发现随着ＤＯＰＥ／ ＤＯＰＣ 比例的改变使Ｃａ２ ＋ － ＡＴＰａｓｅ 构象发生相应的变化。Delipidated SR Ca2+-ATPase was reconstituted into liposomes containing different DOPE/DOPC ratio. It was observed that DOPC is required for the optimal ATPase activity, while DOPE for the calcium uptake and the enhancement of coupling of ATP hydrolysis to Ca2+ transport. To correlate the variation in enzyme activity with the conformational changes, the intrinsic tryptophan fluorescence, fluorescence quenching, as well as intramolecular distances between the fluorescent probes bound to the SR Ca2+-ATPase at different sites using Forster type resonance energy transfer were determined. Obtained data clearly showed that the conformational changes of SR Ca2+-ATPase were occurred in consequence of variation of DOPE/DOPC ratio.

关 键 词：DOPE DOPC 肌质网Ca^2+-ATPase 偶联 构象 

分 类 号：Q55[生物学—生物化学]