Biosynthetic pathways of glycinebetaine in Thalassiosira pseudonana; functional characterization of enzyme catalyzing three-step methylation of glycine
Copyright © 2018 Elsevier Masson SAS. All rights reserved.
| Veröffentlicht in: | Plant physiology and biochemistry : PPB. - 1991. - 127(2018) vom: 10. Juni, Seite 248-255 |
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| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2018
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| Zugriff auf das übergeordnete Werk: | Plant physiology and biochemistry : PPB |
| Schlagworte: | Journal Article Betaine Betaine synthetic pathway Choline dehydrogenase GSDMT Thalassiosira pseudonana 3SCV180C9W Methyltransferases EC 2.1.1.- Choline mehr... |
| Zusammenfassung: | Copyright © 2018 Elsevier Masson SAS. All rights reserved. Betaine (trimethylglycine) is an important compatible solute that accumulates in response to abiotic stresses such as drought and salinity. Biosynthetic pathways of betaine have been extensively studied, but it remains to be clarified on algae. A diatom Thalassiosira pseudonana CCMP1335 is an important component of marine ecosystems. Here we show that the genome sequence of Thalassiosira suggests the presence of two biosynthetic pathways for betaine, via three step methylation of glycine and via two step oxidation of choline. The choline oxidation via choline dehydrogenase was suggested and its sequential characteristics were analyzed. A candidate gene TpORF1 for glycine methylation encodes a protein consisted of 574 amino acids with two putative tandem repeat methyltransferase domains. The TpORF1 was expressed in E. coli, and the purified protein was shown to synthesize betaine via three step methylation of glycine and designated as TpGSDMT. The proteins containing C-terminal half or N-terminal half were expressed in E. coli and exhibited the methyl transferase activities with different substrate specificity for glycine, sarcosine and dimethylglycine. Upregulation of TpGSDMT transcription and betaine levels were observed at high salinity, suggesting the importance of TpGSDMT for salt tolerance in T. pseudonana cells |
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| Beschreibung: | Date Completed 26.07.2018 Date Revised 30.09.2020 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1873-2690 |
| DOI: | 10.1016/j.plaphy.2018.03.032 |