Ahn Taeho, Yun Chul-Ho, Chae Ho Zoon, Kim Hyung-Ryong, Chae Han-Jung
Department of Biochemistry, College of Veterinary Medicine, Chonnam National University, Gwangju, Korea.
FEBS J. 2009 Apr;276(8):2285-91. doi: 10.1111/j.1742-4658.2009.06956.x. Epub 2009 Mar 5.
We investigated the functional activity of recombinant Bax inhibitor-1 reconstituted into liposomes. When proteoliposomes were suspended in acidic solutions, encapsulated Ca(2+) was released from the membranes, as previously suggested [Kim HR, Lee GH, Ha KC, Ahn T, Moon JY, Lee BJ, Cho SG, Kim S, Seo YR, Shin YJ et al. (2008) J Biol Chem283, 15946-15955]. Concomitantly, proton ions were internalized when assayed using the time-dependent change in the fluorescence of the pH-sensitive dye oxonol V entrapped in the proteoliposomes. The influx of proton ions was confirmed by observing tritium accumulation in the membranes. However, the external acidity of the membranes per se did not induce proton ion influx without internalized Ca(2+). These results suggest that reconstituted Bax inhibitor-1 has a Ca(2+)/H(+) antiporter-like activity.
我们研究了重组装入脂质体的Bax抑制剂-1的功能活性。当蛋白脂质体悬浮于酸性溶液中时，如之前所表明的[Kim HR, Lee GH, Ha KC, Ahn T, Moon JY, Lee BJ, Cho SG, Kim S, Seo YR, Shin YJ等人（2008年）《生物化学杂志》283卷，15946 - 15955页]，包封的Ca(2+)从膜中释放出来。同时，当使用包封在蛋白脂质体中的pH敏感染料奥克诺尔V荧光随时间的变化进行测定时，质子离子被内化。通过观察氚在膜中的积累证实了质子离子的流入。然而，膜本身的外部酸性在没有内化Ca(2+)的情况下不会诱导质子离子流入。这些结果表明重组的Bax抑制剂-1具有类似Ca(2+)/H(+)反向转运体的活性。
