Email updates

Keep up to date with the latest news and content from BMC Evolutionary Biology and BioMed Central.

Open Access Highly Accessed Research article

Genome-wide analysis of putative peroxiredoxin in unicellular and filamentous cyanobacteria

Hongli Cui12, Yipeng Wang1, Yinchu Wang12 and Song Qin1*

  • * Corresponding author: Song Qin sqin@yic.ac.cn

  • † Equal contributors

Author affiliations

1 Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Chunhui Road, Yantai 264003, People’s Republic of China

2 University of Chinese Academy of Sciences, Yuquan Road, Beijing 100049, People’s Republic of China

For all author emails, please log on.

Citation and License

BMC Evolutionary Biology 2012, 12:220  doi:10.1186/1471-2148-12-220

Published: 16 November 2012

Abstract

Background

Cyanobacteria are photoautotrophic prokaryotes with wide variations in genome sizes and ecological habitats. Peroxiredoxin (PRX) is an important protein that plays essential roles in protecting own cells against reactive oxygen species (ROS). PRXs have been identified from mammals, fungi and higher plants. However, knowledge on cyanobacterial PRXs still remains obscure. With the availability of 37 sequenced cyanobacterial genomes, we performed a comprehensive comparative analysis of PRXs and explored their diversity, distribution, domain structure and evolution.

Results

Overall 244 putative prx genes were identified, which were abundant in filamentous diazotrophic cyanobacteria, Acaryochloris marina MBIC 11017, and unicellular cyanobacteria inhabiting freshwater and hot-springs, while poor in all Prochlorococcus and marine Synechococcus strains. Among these putative genes, 25 open reading frames (ORFs) encoding hypothetical proteins were identified as prx gene family members and the others were already annotated as prx genes. All 244 putative PRXs were classified into five major subfamilies (1-Cys, 2-Cys, BCP, PRX5_like, and PRX-like) according to their domain structures. The catalytic motifs of the cyanobacterial PRXs were similar to those of eukaryotic PRXs and highly conserved in all but the PRX-like subfamily. Classical motif (CXXC) of thioredoxin was detected in protein sequences from the PRX-like subfamily. Phylogenetic tree constructed of catalytic domains coincided well with the domain structures of PRXs and the phylogenies based on 16s rRNA.

Conclusions

The distribution of genes encoding PRXs in different unicellular and filamentous cyanobacteria especially those sub-families like PRX-like or 1-Cys PRX correlate with the genome size, eco-physiology, and physiological properties of the organisms. Cyanobacterial and eukaryotic PRXs share similar conserved motifs, indicating that cyanobacteria adopt similar catalytic mechanisms as eukaryotes. All cyanobacterial PRX proteins share highly similar structures, implying that these genes may originate from a common ancestor. In this study, a general framework of the sequence-structure-function connections of the PRXs was revealed, which may facilitate functional investigations of PRXs in various organisms.

Keywords:
Peroxiredoxin; Structure; Phylogeny and evolution; Comparative genomics; Cyanobacteria