2012年4月
Discovery and Analysis of Cofactor-dependent Phosphoglycerate Mutase Homologs as Novel Phosphoserine Phosphatases in Hydrogenobacter thermophilus
JOURNAL OF BIOLOGICAL CHEMISTRY
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- 巻
- 287
- 号
- 15
- 開始ページ
- 11934
- 終了ページ
- 11941
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1074/jbc.M111.330621
- 出版者・発行元
- AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Phosphoserine phosphatase (PSP) catalyzes the dephosphorylation of phosphoserine to serine and inorganic phosphate. PSPs, which have been found in all three domains of life, belong to the haloacid dehalogenase-like hydrolase superfamily. However, certain organisms, particularly bacteria, lack a classical PSP gene, although they appear to possess a functional phosphoserine synthetic pathway. The apparent lack of a PSP ortholog in Hydrogenobacter thermophilus, an obligately chemolithoautotrophic and thermophilic bacterium, represented a missing link in serine anabolism because our previous study suggested that serine should be synthesized from phosphoserine. Here, we detected PSP activity in cell-free extracts of H. thermophilus and purified two proteins with PSP activity. Surprisingly, these proteins belonged to the histidine phosphatase superfamily and had been annotated as cofactor-dependent phosphoglycerate mutase (dPGM). However, because they possessed neither mutase activity nor the residues important for the activity, we defined these proteins as novel-type PSPs. Considering the strict substrate specificity toward L-phosphoserine, kinetic parameters, and PSP activity levels in cell-free extracts, these proteins were strongly suggested to function as PSPs in vivo. We also detected PSP activity from "dPGM-like" proteins of Thermus thermophilus and Arabidopsis thaliana, suggesting that PSP activity catalyzed by dPGM-like proteins may be distributed among a broad range of organisms. In fact, a number of bacterial genera, including Firmicutes and Cyanobacteria, were proposed to be strong candidates for possessing this novel type of PSP. These findings will help to identify the missing link in serine anabolism.
- リンク情報
- ID情報
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- DOI : 10.1074/jbc.M111.330621
- ISSN : 0021-9258
- PubMed ID : 22337887
- Web of Science ID : WOS:000302782200032