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MetaCyc Enzyme: 3-phosphoserine aminotransferase / phosphohydroxythreonine aminotransferase

Gene: serC Accession Numbers: EG10946 (MetaCyc), b0907, ECK0898

Synonyms: pdxC, pdxF

Species: Escherichia coli K-12 substr. MG1655

Subunit composition of 3-phosphoserine aminotransferase / phosphohydroxythreonine aminotransferase = [SerC]2

Summary:
The serC-encoded enzyme, phosphoserine/phosphohydroxythreonine aminotransferase, functions in the biosythesis of both serine and pyridoxine, by using different substrates [Lam90]. Pyridoxal 5'-phosphate is a cofactor for both enzyme activities, suggesting that it can act in an autocatalytic fashion, stimulating its own biosynthesis [Drewke96].

[Drewke96] stated that no activity could be observed with non-phosphorylated substrates; however, [Duncan86] was able to use 3-hydroxypyruvate as the substrate for an assay of SerC enzymatic activity. In addition, genetic experiments showed that SerC is a minor alanine transaminase [Kim10, Yoneyama11].

Crystal structures of the enzyme in the unligated form and in complex with the substrate analog α-methyl-L-glutamate have been solved, and a molecular reaction mechanism was proposed [Hester99].

serC is essential for growth on glycerol minimal medium; the growth defect can be rescued by addition of serine and pyridoxol/pyridoxine [Joyce06, Sakai02, Ravnikar87, Clarke73].

Citations: [Wintermute10, Ivancic13]

Locations: cytosol

Map Position: [956,876 -> 957,964]

Molecular Weight of Polypeptide: 39.783 kD (from nucleotide sequence), 39 kD (experimental) [Duncan86 ]

Molecular Weight of Multimer: 79 kD (experimental) [Duncan86]

Unification Links: ASAP:ABE-0003093 , CGSC:171 , DIP:DIP-2896N , EchoBASE:EB0939 , EcoGene:EG10946 , EcoliWiki:b0907 , Mint:MINT-1249760 , ModBase:P23721 , OU-Microarray:b0907 , PortEco:serC , Pride:P23721 , Protein Model Portal:P23721 , RefSeq:NP_415427 , RegulonDB:EG10946 , SMR:P23721 , String:511145.b0907 , UniProt:P23721

Relationship Links: InterPro:IN-FAMILY:IPR000192 , InterPro:IN-FAMILY:IPR003248 , InterPro:IN-FAMILY:IPR015421 , InterPro:IN-FAMILY:IPR015422 , InterPro:IN-FAMILY:IPR015424 , InterPro:IN-FAMILY:IPR020578 , InterPro:IN-FAMILY:IPR022278 , Panther:IN-FAMILY:PTHR21152:SF1 , PDB:Structure:1BJN , PDB:Structure:1BJO , Pfam:IN-FAMILY:PF00266 , Prosite:IN-FAMILY:PS00595

Gene-Reaction Schematic: ?

GO Terms:

Biological Process: GO:0006563 - L-serine metabolic process Inferred from experiment [Saito97]
GO:0006564 - L-serine biosynthetic process Inferred from experiment Inferred by computational analysis [UniProtGOA11a, GOA06, GOA01, Clarke73]
GO:0042823 - pyridoxal phosphate biosynthetic process Inferred from experiment [Lam90]
GO:0008152 - metabolic process Inferred by computational analysis [GOA01]
GO:0008615 - pyridoxine biosynthetic process Inferred by computational analysis [UniProtGOA11a, GOA06]
GO:0008652 - cellular amino acid biosynthetic process Inferred by computational analysis [UniProtGOA11a]
Molecular Function: GO:0004648 - O-phospho-L-serine:2-oxoglutarate aminotransferase activity Inferred from experiment Inferred by computational analysis [GOA06, GOA01a, GOA01, Duncan86]
GO:0030170 - pyridoxal phosphate binding Inferred from experiment Inferred by computational analysis [GOA06, GOA01, Drewke96]
GO:0042803 - protein homodimerization activity Inferred from experiment [Duncan86]
GO:0003824 - catalytic activity Inferred by computational analysis [GOA01]
GO:0008483 - transaminase activity Inferred by computational analysis [UniProtGOA11a]
GO:0016740 - transferase activity Inferred by computational analysis [UniProtGOA11a]
Cellular Component: GO:0005737 - cytoplasm Inferred by computational analysis [UniProtGOA11, UniProtGOA11a, GOA06]
GO:0005829 - cytosol

MultiFun Terms: metabolism biosynthesis of building blocks amino acids serine

Credits:
Imported from EcoCyc 27-May-2014 by Paley S , SRI International


Enzymatic reaction of: 3-phosphoserine aminotransferase

Synonyms: phosphoserine aminotransferase, phosphoserine 2-keto-glutarate transaminase, O-phospho-L-serine:2-oxoglutarate aminotransferase, phosphoserine transaminase

EC Number: 2.6.1.52

3-phospho-L-serine + 2-oxoglutarate <=> L-glutamate + 3-phospho-hydroxypyruvate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.

This reaction is reversible.

Alternative Substrates for 3-phospho-hydroxypyruvate: hydroxypyruvate [Duncan86 ]

In Pathways: superpathway of sulfate assimilation and cysteine biosynthesis , superpathway of serine and glycine biosynthesis I , serine biosynthesis

Credits:
Imported from EcoCyc 27-May-2014 by Paley S , SRI International

Cofactors or Prosthetic Groups: pyridoxal 5'-phosphate [Drewke96]

Kinetic Parameters:

Substrate
Km (μM)
Citations
3-phospho-L-serine
17.0
[Drewke96]
3-phospho-hydroxypyruvate
15.0
[Drewke96]

pH(opt): 8.8 [Drewke96]


Enzymatic reaction of: phosphohydroxythreonine aminotransferase

Synonyms: phosphohydroxythreonine transaminase

EC Number: 2.6.1.52

2-oxo-3-hydroxy-4-phosphobutanoate + L-glutamate <=> 4-phospho-hydroxy-L-threonine + 2-oxoglutarate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.

This reaction is reversible.

In Pathways: superpathway of pyridoxal 5'-phosphate biosynthesis and salvage , pyridoxal 5'-phosphate biosynthesis I

Credits:
Imported from EcoCyc 27-May-2014 by Paley S , SRI International

Cofactors or Prosthetic Groups: pyridoxal 5'-phosphate [Drewke96]

Kinetic Parameters:

Substrate
Km (μM)
Citations
4-phospho-hydroxy-L-threonine
110.0
[Drewke96]

pH(opt): 8.3 [Drewke96]


Sequence Features

Feature Class Location Citations Comment
Cleavage-of-Initial-Methionine 1

 
Chain 2 -> 362

[UniProt09]

UniProt: Phosphoserine aminotransferase;
Amino-Acid-Sites-That-Bind 9

[UniProt10a]

UniProt: L-glutamate;
Amino-Acid-Sites-That-Bind 42

[UniProt10a]

UniProt: L-glutamate;
Protein-Segment 76 -> 77

[UniProt10]

UniProt: Pyridoxal phosphate binding; Sequence Annotation Type: region of interest;
Amino-Acid-Sites-That-Bind 102

[UniProt10a]

UniProt: Pyridoxal phosphate;
Amino-Acid-Sites-That-Bind 153

[UniProt10a]

UniProt: Pyridoxal phosphate;
Amino-Acid-Sites-That-Bind 174

[UniProt10a]

UniProt: Pyridoxal phosphate;
Amino-Acid-Sites-That-Bind 197

[UniProt10a]

UniProt: Pyridoxal phosphate;
N6-pyridoxal-phosphate-Lys-Modification 198

[UniProt11]

UniProt: N6-(pyridoxal phosphate)lysine.
Protein-Segment 239 -> 240

[UniProt10]

UniProt: Pyridoxal phosphate binding; Sequence Annotation Type: region of interest;
Sequence-Conflict 293

[Duncan86, UniProt10a]

Alternate sequence: R; UniProt: (in Ref. 1);

History:
10/20/97 Gene b0907 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10946; confirmed by SwissProt match.


References

Clarke73: Clarke SJ, Low B, Konigsberg WH (1973). "Close linkage of the genes serC (for phosphohydroxy pyruvate transaminase) and serS (for seryl-transfer ribonucleic acid synthetase) in Escherichia coli K-12." J Bacteriol 113(3);1091-5. PMID: 4570768

Drewke96: Drewke C, Klein M, Clade D, Arenz A, Muller R, Leistner E (1996). "4-O-phosphoryl-L-threonine, a substrate of the pdxC(serC) gene product involved in vitamin B6 biosynthesis." FEBS Lett 1996;390(2);179-82. PMID: 8706854

Duncan86: Duncan K, Coggins JR (1986). "The serC-aro A operon of Escherichia coli. A mixed function operon encoding enzymes from two different amino acid biosynthetic pathways." Biochem J 1986;234(1);49-57. PMID: 3518706

GOA01: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

GOA01a: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

GOA06: GOA, SIB (2006). "Electronic Gene Ontology annotations created by transferring manual GO annotations between orthologous microbial proteins."

Hester99: Hester G, Stark W, Moser M, Kallen J, Markovic-Housley Z, Jansonius JN (1999). "Crystal structure of phosphoserine aminotransferase from Escherichia coli at 2.3 A resolution: comparison of the unligated enzyme and a complex with alpha-methyl-l-glutamate." J Mol Biol 286(3);829-50. PMID: 10024454

Ivancic13: Ivancic T, Jamnik P, Stopar D (2013). "Cold shock CspA and CspB protein production during periodic temperature cycling in Escherichia coli." BMC Res Notes 6;248. PMID: 23815967

Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394

Kim10: Kim SH, Schneider BL, Reitzer L (2010). "Genetics and regulation of the major enzymes of alanine synthesis in Escherichia coli." J Bacteriol 192(20);5304-11. PMID: 20729367

Lam90: Lam HM, Winkler ME (1990). "Metabolic relationships between pyridoxine (vitamin B6) and serine biosynthesis in Escherichia coli K-12." J Bacteriol 1990;172(11);6518-28. PMID: 2121717

Ravnikar87: Ravnikar PD, Somerville RL (1987). "Genetic characterization of a highly efficient alternate pathway of serine biosynthesis in Escherichia coli." J Bacteriol 169(6);2611-7. PMID: 3108237

Saito97: Saito K, Takagi Y, Ling HC, Takahashi H, Noji M (1997). "Molecular cloning, characterization and expression of cDNA encoding phosphoserine aminotransferase involved in phosphorylated pathway of serine biosynthesis from spinach." Plant Mol Biol 33(2);359-66. PMID: 9037153

Sakai02: Sakai A, Kita M, Katsuragi T, Tani Y (2002). "serC is involved in vitamin B6 biosynthesis in Escherichia coli but not in Bacillus subtilis." J Biosci Bioeng 93(3);334-7. PMID: 16233211

UniProt09: UniProt Consortium (2009). "UniProt version 15.8 released on 2009-10-01 00:00:00." Database.

UniProt10: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProt10a: UniProt Consortium (2010). "UniProt version 2010-11 released on 2010-11-02 00:00:00." Database.

UniProt11: UniProt Consortium (2011). "UniProt version 2011-11 released on 2011-11-22 00:00:00." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on the manual assignment of UniProtKB Subcellular Location terms in UniProtKB/Swiss-Prot entries."

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

Wintermute10: Wintermute EH, Silver PA (2010). "Emergent cooperation in microbial metabolism." Mol Syst Biol 6;407. PMID: 20823845

Yoneyama11: Yoneyama H, Hori H, Lim SJ, Murata T, Ando T, Isogai E, Katsumata R (2011). "Isolation of a mutant auxotrophic for L-alanine and identification of three major aminotransferases that synthesize L-alanine in Escherichia coli." Biosci Biotechnol Biochem 75(5);930-8. PMID: 21597182


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 38:D473-D479 2010
Page generated by SRI International Pathway Tools version 18.0 on Fri Oct 24, 2014, biocyc11.