title: Computational identification of a new SelD-like family that may participate in sulfur metabolism in hyperthermophilic sulfur-reducing archaea.
abstract: BACKGROUND
  Selenium (Se) and sulfur (S) are closely related elements that exhibit similar chemical properties. Some genes related to S metabolism are also involved in Se utilization in many organisms. However, the evolutionary relationship between the two utilization traits is unclear.
  
  
  RESULTS
  In this study, we conducted a comparative analysis of the selenophosphate synthetase (SelD) family, a key protein for all known Se utilization traits, in all sequenced archaea. Our search showed a very limited distribution of SelD and Se utilization in this kingdom. Interestingly, a SelD-like protein was detected in two orders of Crenarchaeota: Sulfolobales and Thermoproteales. Sequence and phylogenetic analyses revealed that SelD-like protein contains the same domain and conserved functional residues as those of SelD, and might be involved in S metabolism in these S-reducing organisms. Further genome-wide analysis of patterns of gene occurrence in different thermoproteales suggested that several genes, including SirA-like, Prx-like and adenylylsulfate reductase, were strongly related to SelD-like gene. Based on these findings, we proposed a simple model wherein SelD-like may play an important role in the biosynthesis of certain thiophosphate compound.
  
  
  CONCLUSIONS
  Our data suggest novel genes involved in S metabolism in hyperthermophilic S-reducing archaea, and may provide a new window for understanding the complex relationship between Se and S metabolism in archaea.
authors.forename: Gao-Peng
authors.initials: GP
authors.lastname: Li
authors.forename: Liang
authors.initials: L
authors.lastname: Jiang
authors.forename: Jia-Zuan
authors.initials: JZ
authors.lastname: Ni
authors.forename: Qiong
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, P, R, China. yanzhang01@sibs.ac.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics*; D019295:Computational Biology / Q000379:methods*; D017124:Conserved Sequence; D019615:Crenarchaeota / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D019848:Gene Expression Regulation, Archaeal; D010770:Phosphotransferases / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D012643:Selenium / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D013455:Sulfur; D010770:Phosphotransferases; C062762:selenophosphate synthetase; D012643:Selenium