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Functional characterization of aminotransferase involved in serine and aspartate metabolism in a halotolerant cyanobacterium, Aphanothece halophytica
- Source :
- Protoplasma. 256(6)
- Publication Year :
- 2019
-
Abstract
- Aminotransferases catalyze the reversible pyridoxal phosphate-dependent transfer of amino groups from amino acids to oxo acids and play important roles for the balance between carbon and nitrogen metabolism. In this report, four aminotransferases (Ap1-Ap4) from a halotolerant cyanobacterium Aphanothece halophytica were examined. The results revealed that Ap1 and Ap2 exhibited the aspartate:2-oxoglutarate aminotransferase (AspAT) activity whereas Ap2 catalyzed further aminotransferase activities with alanine (AlaAT) and LL-diaminopimelate (an intermediate for the synthesis of Lys/peptidoglycan) as amino donors. Ap4 exhibited bifunctional aminotransferase with phosphoserine (PSAT) and glycine (GGAT) as amino donors. No activity was observed for Ap3. We identified third gene encoding phosphoserine phosphatase (PSP) in phosphorylate serine biosynthetic pathway. The levels of mRNA for Ap2 and ApMurE encoding UDP-N-acetylmuramoyl-L-alanyl-D-glutamate-2,6-diaminopimelate ligase were increased after salt stress. These results suggest the link among photorespiratory metabolite (serine, glycine, glyoxylate), phosphorylate serine biosynthetic pathway and aspartate metabolism via aminotransferases for the synthesis of peptidoglycan and betaine under salt stress conditions.
- Subjects :
- 0106 biological sciences
0301 basic medicine
Alanine
chemistry.chemical_classification
Aspartic Acid
Phosphoserine phosphatase
Cell Biology
Plant Science
General Medicine
Cyanobacteria
01 natural sciences
Amino acid
Serine
03 medical and health sciences
chemistry.chemical_compound
030104 developmental biology
chemistry
Biochemistry
Phosphoserine
Glycine
Phosphoserine Aminotransferase
Peptidoglycan
Transaminases
010606 plant biology & botany
Subjects
Details
- ISSN :
- 16156102
- Volume :
- 256
- Issue :
- 6
- Database :
- OpenAIRE
- Journal :
- Protoplasma
- Accession number :
- edsair.doi.dedup.....fe10a7deb7b3296659c601b0254f866c