Structures of the thermophilic F1-ATPase ε subunit suggesting ATP-regulated arm motion of its C-terminal domain in F1
Structures of the thermophilic F1-ATPase ε subunit suggesting ATP-regulated arm motion of its C-terminal domain in F1
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DOI：
10.1073/pnas.0701045104
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发表时间：
2007-07-03
影响因子：
11.1
通讯作者：
Akutsu, Hideo
中科院分区：
文献类型：
--
作者：
Yagi, Hiromasa;Kajiwara, Nobumoto;Akutsu, Hideo
细菌和叶绿体 FoF1-ATP 合酶的 epsilon 亚基调节其 ATP 水解活性。在这里，我们以 1.9 埃的分辨率报道了嗜热芽孢杆菌 PS3 的 ATP 结合 E 亚基的晶体结构。 C 端两个 α 螺旋折叠成发夹，位于 13 夹心结构上，如大肠杆菌报道的那样。先前未描述的 ATP 结合基序 I(L)DXXRA 可识别 ATP 以及三个精氨酸和一个谷氨酸残基。根据 NMR 的判断，大肠杆菌 e 亚基以类似的方式结合 ATP。我们还通过 NMR 确定了 PS3 E 亚基 C 端结构域的溶液结构和整个分子的弛豫参数。在 ATIP 存在的情况下，两个螺旋折叠成发夹，但在 ATP 不存在的情况下延伸。后者的结构具有更多的螺旋区域并且比前者更加灵活。这些结果表明，e C 末端结构域可以响应 ATP 浓度变化而进行类似臂的运动，从而有助于 FoF1-ATP 合酶的调节。
The epsilon subunit of bacterial and chloroplast FoF1-ATP synthases modulates their ATP hydrolysis activity. Here, we report the crystal structure of the ATP-bound E subunit from a thermophilic Bacillus PS3 at 1.9-angstrom resolution. The C-terminal two a-helices were folded into a hairpin, sitting on the 13 sandwich structure, as reported for Escherichia coli. A previously undescribed ATP binding motif, l(L)DXXRA, recognizes ATP together with three arginine and one glutamate residues. The E. coli e subunit binds ATP in a similar manner, as judged on NMR. We also determined solution structures of the C-terminal domain of the PS3 E subunit and relaxation parameters of the whole molecule by NMR. The two helices fold into a hairpin in the presence of ATIP but extend in the absence of ATP. The latter structure has more helical regions and is much more flexible than the former. These results suggest that the e C-terminal domain can undergo an arm-like motion in response to an ATP concentration change and thereby contribute to regulation of FoF1-ATP synthase.