PIRSF000525

Phosphoserine aminotransferase

PIRSF entry
Member databasePIRSF
PIRSF typefamily
Short nameSerC

Description

Phosphoserine aminotransferase (PSAT) is involved in serine biosynthesis. The enzyme catalyses the reversible conversion of 3-phosphohydroxypyruvate to L-phosphoserine. PSAT from Escherichia coli has been shown to be a homodimer of Mr79,000 with a conserved Lys that binds covalently to pyridoxal phosphate (PLP). PSAT is a vitamin B6-dependent enzyme and belongs to the alpha family of PLP enzymes. PSAT is also classified as a member of the aspartate aminotransferase family of PLP enzymes
[3]
. According to the structural classification of PLP-dependent enzymes
[4]
, PSAT belongs to the fold type I, where it is allocated to a separated subclass. The mechanism of action in all these enzymes is similar: PLP combines with an alpha-amino acid to form a compound called a Schiff base or aldimine intermediate, which, depending on the reaction, is the substrate in four kinds of reactions (1) transamination (movement of amino groups), (2) racemization (redistribution of enantiomers), (3) decarboxylation (removing COOH groups), and (4) various side-chain reactions depending on the enzyme involved.

For additional information please see
[5, 1, 2]
.

References

1.Enzyme adaptation to alkaline pH: atomic resolution (1.08 A) structure of phosphoserine aminotransferase from Bacillus alcalophilus. Dubnovitsky AP, Kapetaniou EG, Papageorgiou AC. Protein Sci. 14, 97-110, (2005). View articlePMID: 15608117

2.Crystallization and preliminary X-ray analysis of phosphoserine aminotransferase from Bacillus circulans subsp. alkalophilus. Moser M, Muller R, Battchikova N, Koivulehto M, Korpela T, Jansonius JN. Protein Sci. 5, 1426-8, (1996). View articlePMID: 8819175

3.Structure, evolution and action of vitamin B6-dependent enzymes. Jansonius JN. Curr. Opin. Struct. Biol. 8, 759-69, (1998). View articlePMID: 9914259

4.Modeling of the spatial structure of eukaryotic ornithine decarboxylases. Grishin NV, Phillips MA, Goldsmith EJ. Protein Sci. 4, 1291-304, (1995). View articlePMID: 7670372

5.Phosphoserine aminotransferase from Bacillus circulans subsp. alkalophilus: purification, gene cloning and sequencing. Battchikova N, Himanen JP, Ahjolahti M, Korpela T. Biochim. Biophys. Acta 1295, 187-94, (1996). View articlePMID: 8695645

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