Reviewed, UniProtKB/Swiss-Prot P23721 (SERC_ECOLI)

Names and origin

Protein names

Recommended name:
    Phosphoserine aminotransferase
    EC=2.6.1.52
Alternative name(s):
    Phosphohydroxythreonine aminotransferase
      Short name=PSAT

Gene names

Name:	serC
Synonyms:	pdxC, pdxF
Ordered Locus Names:	b0907, JW0890

Organism

Escherichia coli (strain K12) [Complete proteome] [HAMAP]

Taxonomic identifier

83333 [NCBI]

Taxonomic lineage

Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacteriales › Enterobacteriaceae › Escherichia

Protein attributes

Sequence length	362 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Catalyzes the reversible conversion of 3-phosphohydroxypyruvate to phosphoserine and of 3-hydroxy-2-oxo-4-phosphonooxybutanoate to phosphohydroxythreonine. Is involved in both pyridoxine and serine biosynthesis. Ref.8
Catalytic activity	O-phospho-L-serine + 2-oxoglutarate = 3-phosphonooxypyruvate + L-glutamate. Ref.8 4-phosphonooxy-L-threonine + 2-oxoglutarate = (3R)-3-hydroxy-2-oxo-4-phosphonooxybutanoate + L-glutamate. Ref.8
Cofactor	Binds 1 pyridoxal phosphate per subunit. Ref.8 Ref.9
Pathway	Amino-acid biosynthesis; L-serine biosynthesis; L-serine from 3-phospho-D-glyceric acid: step 2/3. Ref.7 Cofactor biosynthesis; pyridoxine 5'-phosphate biosynthesis; pyridoxine 5'-phosphate from D-erythrose 4-phosphate: step 3/5. Ref.7
Subunit structure	Homodimer. Ref.9
Subcellular location	Cytoplasm. HAMAP MF_00160
Sequence similarities	Belongs to the class-V pyridoxal-phosphate-dependent aminotransferase family. SerC subfamily.
biophysicochemical properties	Kinetic parameters: No activity could be observed with non-phosphorylated substrates. KM=15 µM for 3-phosphonooxypyruvate HAMAP MF_00160 KM=17 µM for O(3)-phospho-L-serine KM=110 µM for 4-phosphonooxy-L-threonine Vmax=45 nmol/sec/mg enzyme with 3-phosphonooxypyruvate as substrate Vmax=9.9 nmol/sec/mg enzyme with O(3)-phospho-L-serine as substrate Vmax=3.8 nmol/sec/mg enzyme with 4-phosphonooxy-L-threonine as substrate pH dependence: Optimum pH is 7.5-8.8.

Ontologies

Keywords
Biological process	Amino-acid biosynthesis Pyridoxine biosynthesis Serine biosynthesis
Cellular component	Cytoplasm
Ligand	Pyridoxal phosphate
Molecular function	Aminotransferase Transferase
Technical term	3D-structure Complete proteome Direct protein sequencing
Gene Ontology (GO)
Biological process	L-serine biosynthetic process Inferred from electronic annotation. Source: HAMAP pyridoxine biosynthetic process Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	cytoplasm Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	O-phospho-L-serine:2-oxoglutarate aminotransferase activity Inferred from electronic annotation. Source: HAMAP protein binding Inferred from physical interaction. Source: IntAct pyridoxal phosphate binding Inferred from electronic annotation. Source: HAMAP
Complete GO annotation...

Binary interactions

With	Entry	#Exp.	IntAct	Notes
asnA	P00963	1	EBI-557952,EBI-1117481
dnaK	P0A6Y8	1	EBI-557952,EBI-542092
selB	P14081	1	EBI-557952,EBI-551705

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Initiator methionine

1

1

Removed Ref.5

Chain

2 – 362

361

Phosphoserine aminotransferase HAMAP MF_00160

PRO_0000150167

Regions

Region

76 – 77

2

Pyridoxal phosphate binding HAMAP MF_00160

Region

239 – 240

2

Pyridoxal phosphate binding HAMAP MF_00160

Sites

Binding site

9

1

L-glutamate HAMAP MF_00160

Binding site

42

1

L-glutamate HAMAP MF_00160

Binding site

102

1

Pyridoxal phosphate HAMAP MF_00160

Binding site

153

1

Pyridoxal phosphate HAMAP MF_00160

Binding site

174

1

Pyridoxal phosphate HAMAP MF_00160

Binding site

197

1

Pyridoxal phosphate HAMAP MF_00160

Amino acid modifications

Modified residue

198

1

N6-(pyridoxal phosphate)lysine

Experimental info

Sequence conflict

293

1

A → R Ref.1

Secondary structure

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362

Helix Strand Turn

Details...

Beta strand

9 – 11

3

Helix

16 – 24

9

Beta strand

26 – 28

3

Helix

29 – 31

3

Beta strand

32 – 34

3

Helix

36 – 38

3

Helix

44 – 61

18

Beta strand

67 – 74

8

Helix

75 – 87

13

Beta strand

93 – 100

8

Helix

101 – 110

10

Turn

111 – 113

3

Beta strand

114 – 120

7

Beta strand

122 – 125

4

Beta strand

128 – 131

4

Helix

134 – 136

3

Beta strand

146 – 148

3

Beta strand

150 – 152

3

Turn

153 – 156

4

Beta strand

171 – 174

4

Turn

176 – 180

5

Helix

186 – 188

3

Beta strand

190 – 195

6

Turn

196 – 200

5

Beta strand

206 – 211

6

Helix

212 – 214

3

Helix

224 – 226

3

Helix

228 – 233

6

Turn

234 – 236

3

Helix

243 – 258

16

Helix

261 – 282

22

Beta strand

284 – 287

4

Helix

292 – 294

3

Beta strand

297 – 306

10

Helix

307 – 309

3

Helix

310 – 319

10

Turn

329 – 331

3

Beta strand

333 – 337

5

Helix

344 – 361

18

Sequences

	Sequence		Length	Mass (Da)
	P23721-1 [UniParc]. Last modified January 23, 2007. Version 4. Checksum: F6A58CBF9FA22BC9	FASTA	362	39,783
	10 20 30 40 50 60 MAQIFNFSSG PAMLPAEVLK QAQQELRDWN GLGTSVMEVS HRGKEFIQVA EEAEKDFRDL 70 80 90 100 110 120 LNVPSNYKVL FCHGGGRGQF AAVPLNILGD KTTADYVDAG YWAASAIKEA KKYCTPNVFD 130 140 150 160 170 180 AKVTVDGLRA VKPMREWQLS DNAAYMHYCP NETIDGIAID ETPDFGADVV VAADFSSTIL 190 200 210 220 230 240 SRPIDVSRYG VIYAGAQKNI GPAGLTIVIV REDLLGKANI ACPSILDYSI LNDNGSMFNT 250 260 270 280 290 300 PPTFAWYLSG LVFKWLKANG GVAEMDKINQ QKAELLYGVI DNSDFYRNDV AKANRSRMNV 310 320 330 340 350 360 PFQLADSALD KLFLEESFAA GLHALKGHRV VGGMRASIYN AMPLEGVKAL TDFMVEFERR HG

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"The serC-aro A operon of Escherichia coli. A mixed function operon encoding enzymes from two different amino acid biosynthetic pathways." Duncan K., Coggins J.R. Biochem. J. 234:49-57(1986) [PubMed: 3518706] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: K12.
[2]	"A 718-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 12.7-28.0 min region on the linkage map." Oshima T., Aiba H., Baba T., Fujita K., Hayashi K., Honjo A., Ikemoto K., Inada T., Itoh T., Kajihara M., Kanai K., Kashimoto K., Kimura S., Kitagawa M., Makino K., Masuda S., Miki T., Mizobuchi K. , Mori H., Motomura K., Nakamura Y., Nashimoto H., Nishio Y., Saito N., Sampei G., Seki Y., Tagami H., Takemoto K., Wada C., Yamamoto Y., Yano M., Horiuchi T. DNA Res. 3:137-155(1996) [PubMed: 8905232] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / W3110 / ATCC 27325 / DSM 5911.
[3]	"The complete genome sequence of Escherichia coli K-12." Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V., Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F., Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B., Shao Y. Science 277:1453-1474(1997) [PubMed: 9278503] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / MG1655 / ATCC 47076.
[4]	"Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110." Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S., Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T. Mol. Syst. Biol. 2:E1-E5(2006) [PubMed: 16738553] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / W3110 / ATCC 27325 / DSM 5911.
[5]	"Comparing the predicted and observed properties of proteins encoded in the genome of Escherichia coli K-12." Link A.J., Robison K., Church G.M. Electrophoresis 18:1259-1313(1997) [PubMed: 9298646] [Abstract] Cited for: PROTEIN SEQUENCE OF 2-13. Strain: K12 / EMG2.
[6]	"Extensive homology between the Escherichia coli K-12 SerC(PdxF) aminotransferase and a protein encoded by a progesterone-induced mRNA in rabbit and human endometria." van der Zel A., Lam H.-M., Winkler M.E. Nucleic Acids Res. 17:8379-8379(1989) [PubMed: 2682527] [Abstract] Cited for: SIMILARITY TO RABBIT EPIP.
[7]	"Metabolic relationships between pyridoxine (vitamin B6) and serine biosynthesis in Escherichia coli K-12." Lam H.-M., Winkler M.E. J. Bacteriol. 172:6518-6528(1990) [PubMed: 2121717] [Abstract] Cited for: FUNCTON, PATHWAY. Strain: K12.
[8]	"4-O-phosphoryl-L-threonine, a substrate of the pdxC(serC) gene product involved in vitamin B6 biosynthesis." Drewke C., Klein M., Clade D., Arenz A., Mueller R., Leistner E. FEBS Lett. 390:179-182(1996) [PubMed: 8706854] [Abstract] Cited for: FUNCTION, CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES, COFACTOR.
[9]	"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." Hester G., Stark W., Moser M., Kallen J., Markovic-Housley Z., Jansonius J.N. J. Mol. Biol. 286:829-850(1999) [PubMed: 10024454] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.3 ANGSTROMS) OF 3-362 IN COMPLEX WITH PLP AND SUBSTRATE ANALOG, SUBUNIT, CATALYTIC MECHANISM, PYRIDOXAL PHOSPHATE AT LYS-198.

Cross-references

Sequence databases

EMBLGenBankDDBJ

U00096 Genomic DNA. Translation: AAC73993.1.
AP009048 Genomic DNA. Translation: BAA35642.1.

PIR

B64830.

RefSeq

AP_001537.1.
NP_415427.1.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1BJN	X-ray	2.30	A/B	3-362	[»]
1BJO	X-ray	2.80	A	3-362	[»]
			B	3-362	[»]

ModBase

Search...

Protein-protein interaction databases

DIP

DIP:2896N.

IntAct

P23721. 9 interactions.

2-D gel databases

SWISS-2DPAGE

P23721.

2DBase-Ecoli

P23721.

Genome annotation databases

GeneID

945527.

GenomeReviews

Gene locus JW0890 in contig AP009048_GR.
Gene locus b0907 in contig U00096_GR.

KEGG

ecj:JW0890.
eco:b0907.

Organism-specific databases

EchoBASE

EB0939.

EcoGene

EG10946. serC.

CMR

Search...

Phylogenomic databases

HOGENOM

P23721.

OMA

P23721. SMYNTPP.

Enzyme and pathway databases

BioCyc

EcoCyc:PSERTRANSAM-MON.
MetaCyc:PSERTRANSAM-MON.

Family and domain databases

HAMAP

MF_00160.
[Tree]

InterPro

IPR000192. Aminotrans_V/Cys_dSase.
IPR003248. Pser_amintransf.
IPR015421. PyrdxlP-dep_Trfase_major_sub1.
IPR015422. PyrdxlP-dep_Trfase_major_sub2.
[Graphical view]

Gene3D

G3DSA:3.40.640.10. PyrdxlP-dep_Trfase_major_sub1. 1 hit.
G3DSA:3.90.1150.10. PyrdxlP-dep_Trfase_major_sub2. 1 hit.

Pfam

PF00266. Aminotran_5. 1 hit.
[Graphical view]

ProDom

PD001544. Pser_amintransf. 1 hit.
[Graphical view] [Entries sharing at least one domain]

TIGRFAMs

TIGR01364. serC_1. 1 hit.

PROSITE

PS00595. AA_TRANSFER_CLASS_5. 1 hit.
[Graphical view]

ProtoNet

Search...

Entry information

Entry name

SERC_ECOLI

Accession

Primary (citable) accession number: P23721
Secondary accession number(s): P78266

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 1991
Last sequence update:	January 23, 2007
Last modified:	June 16, 2009
This is version 101 of the entry and version 4 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HAMAP (High-quality Automated and Manual Annotation of microbial Proteomes)