The Conformation of the ε- and γ-Subunits within theEscherichia coli F1 ATPase*
The Conformation of the ε- and γ-Subunits within theEscherichia coli F1 ATPase*
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DOI：
10.1074/jbc.m107536200
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发表时间：
2001-12
期刊：
影响因子：
--
通讯作者：
A. Hausrath;R. Capaldi;B. Matthews
中科院分区：
文献类型：
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作者：
A. Hausrath;R. Capaldi;B. Matthews
F1是无处不在的F1F0 ATP合酶的水溶性部分。它的结构包括三个α-和三个β-亚基，排列成一个六聚体圆盘，加上一个穿透圆盘中心的γ-亚基，类似于一个轴。最近Hausrath等人（Hausrath, a.c., gr<s:1> ber， G., Matthews, b.w., and Capaldi, r.a., 1999）。学会科学。us . A. 96, 13697-13702)以4.4-Å分辨率获得了大肠杆菌1的电子密度图，其中可以看到γ-亚基的线圈状α-螺旋从α3β3六聚体的基部延伸45 Å。随后描述了大肠杆菌γ-亚基与ε复合物的截断形式的结构(Rodgers, a.j.w., and Wilce, m.c.j. (2000) Nat. Struct。生物学杂志，7,1051-1054)。本研究根据新获得的γ-和ε-亚基数据，对大肠杆菌F1的4.4-Å分辨率电子密度图进行了重新评价。结果表明，F1配合物的图谱与分离亚基的结构一致。当大肠杆菌与牛肉心脏的大肠杆菌进行比较时，大肠杆菌γ-和ε-亚基的结构与牛酶的对应结构大致相似，但在位置上发生了重大变化。特别是，沿F1轴的两个长而卷曲的α-螺旋既展开又旋转。ε-亚基绕轴旋转81°，净平移约23 Å。这些大规模的构象变化反映了α3 - β3六聚体中γ-亚基旋转过程中不同的功能状态。
F1 is the water-soluble portion of the ubiquitous F1F0 ATP synthase. Its structure includes three α- and three β-subunits, arranged as a hexameric disc, plus a γ-subunit that penetrates the center of the disc akin to an axle. Recently Hausrath et al. (Hausrath, A. C., Grüber, G., Matthews, B. W., and Capaldi, R. A. (1999) Proc. Natl. Acad. Sci. U. S. A. 96, 13697–13702) obtained an electron density map of E. coliF1 at 4.4-Å resolution in which the coiled-coil α-helices of the γ-subunit could be seen to extend 45 Å from the base of the α3β3 hexamer. Subsequently the structure of a truncated form of the E. coli γ-subunit in complex with ε has been described (Rodgers, A. J. W., and Wilce, M. C. J. (2000) Nat. Struct. Biol. 7, 1051–1054). In the present study the 4.4-Å resolution electron density map of E. coli F1 is re-evaluated in light of the newly available data on the γ- and ε-subunits. It is shown that the map of the F1 complex is consistent with the structure of the isolated subunits. When E. coliF1 is compared with that from beef heart, the structures of the E. coli γ- and ε-subunits are seen to be generally similar to their counterparts in the bovine enzyme but to undergo major shifts in position. In particular, the two long, coiled-coil α-helices that lie along the axis of F1 both unwind and rotate. Also the ε-subunit rotates around the axis by 81° and undergoes a net translation of about 23 Å. It is argued that these large-scale changes in conformation reflect distinct functional states that occur during the rotation of the γ-subunit within the α3β3 hexamer.