The structure of the chloroplast F1-ATPase at 3.2 Å resolution
The structure of the chloroplast F1-ATPase at 3.2 Å resolution
复制标题
DOI：
10.1074/jbc.m008015200
复制
发表时间：
2001-01-12
影响因子：
4.8
通讯作者：
Pohl, E
中科院分区：
文献类型：
--
作者：
Groth, G;Pohl, E
根据牛线粒体酶的同源结构，通过分子置换确定了菠菜叶绿体F-1-ATP酶的结构，分辨率为3.2 A。结晶的复合物含有四个不同的亚基，化学计量为α（3）β（3）γ（1）。在结晶之前除去亚基δ以改善晶体的衍射。非催化性α亚基和催化性β亚基的总体结构与线粒体和嗜热亚基的结构高度相似。然而，在叶绿体酶的晶体结构中，所有的α-和β-亚基都采用封闭构象，似乎不含结合的腺嘌呤核苷酸。空间群R32中的叠加晶体学对称性损害了复合物中γ-和γ-亚基的精确追踪。然而，在α（3），β（3）-亚复合物的核心处存在明显的电子密度，其可能代表γ-亚基的C-末端结构域。菠菜叶绿体F-1的结构具有植物毒素tentoxin的潜在结合位点，在杯-界面靠近β-Asp（83）处的插入和在N-末端β-桶结构域中的β-Gly（56）-Asn（60）的插入可能增加复合物的热稳定性。该结构可能代表ATP酶的非活性潜伏状态，这是叶绿体和蓝藻酶所特有的。
The structure of the F-1-ATPase from spinach chloroplasts was determined to 3.2 A resolution by molecular replacement based on the homologous structure of the bovine mitochondrial enzyme. The crystallized complex contains four different subunits in a stoichiometry of alpha (3)beta (3)gamma epsilon. Subunit delta was removed before crystallization to improve the diffraction of the crystals. The overall structure of the noncatalytic alpha -subunits and the catalytic beta -subunits is highly similar to those of the mitochondrial and thermophilic subunits. However, in the crystal structure of the chloroplast enzyme, all alpha- and beta -subunits adopt a closed conformation and appear to contain no bound adenine nucleotides. The superimposed crystallographic symmetry in the space group R32 impaired an exact tracing of the gamma- and epsilon -subunits in the complex. However, clear electron density was present at the core of the alpha (3),beta (3)-subcomplex, which probably represents the C-terminal domain of the gamma -subunit, The structure of the spinach chloroplast F-1 has a potential binding site for the phytotoxin, tentoxin, at the cup-interface near beta Asp(83) and an insertion from beta Gly(56)-Asn(60) in the N-terminal beta -barrel domain probably increases the thermal stability of the complex. The structure probably represents an inactive latent state of the ATPase, which is unique to chloroplast and cyanobacterial enzymes.