National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, China.
PLoS One. 2013 Jul 29;8(7):e70099. doi: 10.1371/journal.pone.0070099. Print 2013.
H(+)-translocating inorganic pyrophosphatases (H(+)-PPase) were recognized as the original energy donors in the development of plants. A large number of researchers have shown that H(+)-PPase could be an early-originated protein that participated in many important biochemical and physiological processes. In this study we cloned 14 novel sequences from 7 eremophytes: Sophora alopecuroid (Sa), Glycyrrhiza uralensis (Gu), Glycyrrhiza inflata (Gi), Suaeda salsa (Ss), Suaeda rigida (Sr), Halostachys caspica (Hc), and Karelinia caspia (Kc). These novel sequences included 6 ORFs and 8 fragments, and they were identified as H(+)-PPases based on the typical conserved domains. Besides the identified domains, sequence alignment showed that there still were two novel conserved motifs. A phylogenetic tree was constructed, including the 14 novel H(+)-PPase amino acid sequences and the other 34 identified H(+)-PPase protein sequences representing plants, algae, protozoans and bacteria. It was shown that these 48 H(+)-PPases were classified into two groups: type I and type II H(+)-PPase. The novel 14 eremophyte H(+)-PPases were classified into the type I H(+)-PPase. The 3D structures of these H(+)-PPase proteins were predicted, which suggested that all type I H(+)-PPases from higher plants and algae were homodimers, while other type I H(+)-PPases from bacteria and protozoans and all type II H(+)-PPases were monomers. The 3D structures of these novel H(+)-PPases were homodimers except for SaVP3, which was a monomer. This regular structure could provide important evidence for the evolutionary origin and study of the relationship between the structure and function among members of the H(+)-PPase family.
H(+)转运无机焦磷酸酶（H(+) - PPase）被认为是植物发育过程中的原始能量供体。大量研究表明，H(+) - PPase 可能是一种早期起源的蛋白质，参与了许多重要的生化和生理过程。在这项研究中，我们从 7 种旱生植物中克隆了 14 个新序列：苦豆子（Sa）、甘草（Gu）、胀果甘草（Gi）、盐角草（Ss）、盐节木（Sr）、滨藜（Hc）和白刺（Kc）。这些新序列包括 6 个 ORF 和 8 个片段，根据典型的保守结构域鉴定为 H(+) - PPase。除了鉴定出的结构域外，序列比对显示还有两个新的保守基序。构建了一个系统发育树，包括 14 个新的 H(+) - PPase 氨基酸序列和另外 34 个已鉴定的代表植物、藻类、原生动物和细菌的 H(+) - PPase 蛋白序列。结果表明，这 48 个 H(+) - PPase 分为两组：I 型和 II 型 H(+) - PPase。新的 14 种旱生植物 H(+) - PPase 被归类为 I 型 H(+) - PPase。预测了这些 H(+) - PPase 蛋白的 3D 结构，表明所有来自高等植物和藻类的 I 型 H(+) - PPase 都是同源二聚体，而其他来自细菌和原生动物的 I 型 H(+) - PPase 和所有 II 型 H(+) - PPase 都是单体。除了 SaVP3 是单体外，这些新的 H(+) - PPase 的 3D 结构都是同源二聚体。这种规则的结构为 H(+) - PPase 家族成员的进化起源和结构与功能关系的研究提供了重要证据。
