Structures of the Carbon-Phosphorus Lyase Complex Reveal the Binding Mode of the NBD-like PhnK.
Structures of the Carbon-Phosphorus Lyase Complex Reveal the Binding Mode of the NBD-like PhnK.
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DOI：
10.1016/j.str.2015.11.009
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发表时间：
2016-01-05
期刊：
影响因子：
--
通讯作者：
Zhang J
中科院分区：
文献类型：
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作者：
Yang K;Ren Z;Raushel FM;Zhang J
碳-磷（C-P）裂解酶复合物是细菌将未活化的膦酸盐代谢为磷酸盐所必需的。使用单粒子冷冻电子显微镜，我们确定了两种结构的C-P裂解酶核心复合物PhnG 2 H2 I2 J2，有或没有PhnK，分别。PhnG 2 H2 I2 J2是一个双重对称的杂八聚体。其两个PhnJ亚基为PhnK提供两个相同的结合位点。由于空间位阻，只有一个PhnK与PhnG 2 H2 I2 J2结合。PhnK与ATP结合盒（ABC）转运蛋白的核苷酸结合结构域（NBD）同源。PhnK的α-螺旋3和4与PhnJ的α-螺旋6和环（残基227-230）结合，其结合模式与NBD与其跨膜伴侣的结合模式不同。此外，PhnK的结合暴露了位于PhnJ和PhnH之间界面附近的PhnJ的活性位点残基Gly 32。这些结构信息为进一步阐明C-P裂解酶的反应机理提供了基础。
The carbon-phosphorus (C-P) lyase complex is essential for the metabolism of unactivated phosphonates to phosphate in bacteria. Using single-particle cryo-electron microscopy, we determined two structures of the C-P lyase core complex PhnG2H2I2J2, with or without PhnK, respectively. PhnG2H2I2J2 is a two-fold symmetric hetero-octamer. Its two PhnJ subunits provide two identical binding sites for PhnK. Only one PhnK binds to PhnG2H2I2J2 due to steric hindrance. PhnK is homologous to the nucleotide-binding domain (NBD) of ATP-Binding Cassette (ABC) transporters. The α-helices 3 and 4 of PhnK bind to the α-helix 6 and a loop (residues 227–230) of PhnJ, in a different mode from the binding of NBDs to their trans-membrane partners. Moreover, binding of PhnK exposes the active site residue, Gly32 of PhnJ, located near the interface between PhnJ and PhnH. This structural information provides a basis for further deciphering the reaction mechanism of the C-P lyase.