Isolation and Characterization of a Conserved Domain in the Eremophyte H+-PPase Family

Xianlong Zhang,Shuangxia Jin,Yanqin Wang,Longfu Zhu,Maojun Wang,Baohong Zhang

doi:10.1371/journal.pone.0070099

Xianlong Zhang, Shuangxia Jin

Open Access

https://doi.org/10.1371/journal.pone.0070099

Copy DOI

Journal: PLoS ONE	Publication Date: Jul 29, 2013
Citations: 33	License type: CC BY 4.0

Affiliation: Huazhong Agricultural University, Tarim University

Abstract

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.

Highlights

A basic property of life is the ability of an organism to regulate cellular pH and ion homeostasis for its normal growth and development
Sequences A total of 6 complete ORF sequences and 8 conserved region fragments of H+-PPase were cloned from 7 donor eremophytes (Figure S1) by RT-PCR and the rapid-amplification of cDNA ends (RACE) method, respectively
2 ORFs and 1 fragment were from Sophora alopecuroid (Sa), 2 ORFs were from Glycyrrhiza uralensis Fisch L. (Gu) and 1 ORF from Glycyrrhiza inflata Batalin L. (Gi), while 2 fragments were from salsa L. (Ss), 1 fragment was from Suaeda rigida (Sr), 3 fragments were from Halostachys caspica L. (Hc) and the remaining ORF and fragment were from Karelinia caspia (Pall.) L. (Kc)

Summary

Introduction

A basic property of life is the ability of an organism to regulate cellular pH and ion homeostasis for its normal growth and development. The concerted action of H+-translocating enzymes (H+-pumps) and cation/H+ exchangers are vital to establish and maintain optimal ion and pH gradients. These gradients exist between the cytoplasm and vacuole and between the cytoplasm and rhizosphere and are essential for cell function and plant development [1,2,3]. Seufferheld et al [9] investigated the divergence of protein domains in the H+-PPase molecules, and domain PF03030 was found to be shared by 31 species in Eukarya, 231 in Bacteria, and 17 in Archaea This domain is associated with the function of H+-PPase, namely, to hydrolyze diphosphate to phosphate and H2O or synthesize diphosphate using phosphate as a substrate. Native H+-PPases are divided into two types (type I and type II)

Methods

Results

Discussion

Conclusion