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Protein

Homoserine O-acetyltransferase

Gene

metXA

Organism
Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Transfers an acetyl group from acetyl-CoA to L-homoserine, forming acetyl-L-homoserine (PubMed:10913262, Ref. 3). Utilizes a ping-pong kinetic mechanism in which the acetyl group of acetyl-CoA is initially transferred to the enzyme to form a acetyl-enzyme intermediate before subsequent transfer to homoserine to form the final product, O-acetylhomoserine (PubMed:10913262).2 Publications

Catalytic activityi

Acetyl-CoA + L-homoserine = CoA + O-acetyl-L-homoserine.UniRule annotation2 Publications

Kineticsi

kcat is 92 sec(-1) with acetyl-CoA and L-homoserine as substrates (at 25 degrees Celsius and pH 7.5) (PubMed:10913262). kcat is 5 sec(-1) (Ref. 3).2 Publications
  1. KM=130 µM for L-homoserine (at 25 degrees Celsius and pH 7.5)1 Publication
  2. KM=570 µM for L-homoserine1 Publication
  3. KM=140 µM for acetyl-CoA (at 25 degrees Celsius and pH 7.5)1 Publication
  4. KM=586 µM for acetyl-CoA1 Publication
  5. KM=90 µM for propionyl-CoA (at 25 degrees Celsius and pH 7.5)1 Publication
  6. KM=130 µM for crotonyl-CoA (at 25 degrees Celsius and pH 7.5)1 Publication
  7. KM=210 µM for butyryl-CoA (at 25 degrees Celsius and pH 7.5)1 Publication
  8. KM=280 µM for glutaryl-CoA (at 25 degrees Celsius and pH 7.5)1 Publication
  9. KM=360 µM for succinyl-CoA (at 25 degrees Celsius and pH 7.5)1 Publication
  10. KM=1400 µM for 4-nitrophenyl acetate (at 25 degrees Celsius and pH 7.5)1 Publication
  11. KM=4700 µM for D-homoserine (at 25 degrees Celsius and pH 7.5)1 Publication

    Pathwayi: L-methionine biosynthesis via de novo pathway

    This protein is involved in step 1 of the subpathway that synthesizes O-acetyl-L-homoserine from L-homoserine.UniRule annotation
    Proteins known to be involved in this subpathway in this organism are:
    1. Homoserine O-acetyltransferase (metXA)
    This subpathway is part of the pathway L-methionine biosynthesis via de novo pathway, which is itself part of Amino-acid biosynthesis.
    View all proteins of this organism that are known to be involved in the subpathway that synthesizes O-acetyl-L-homoserine from L-homoserine, the pathway L-methionine biosynthesis via de novo pathway and in Amino-acid biosynthesis.

    Sites

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Active sitei143NucleophileUniRule annotation1 Publication1
    Binding sitei212SubstrateUniRule annotation1 Publication1
    Active sitei304UniRule annotation1 Publication1
    Active sitei337UniRule annotation1 Publication1
    Binding sitei338SubstrateUniRule annotation1 Publication1

    GO - Molecular functioni

    • homoserine O-acetyltransferase activity Source: UniProtKB

    GO - Biological processi

    Keywordsi

    Molecular functionAcyltransferase, Transferase
    Biological processAmino-acid biosynthesis, Methionine biosynthesis

    Enzyme and pathway databases

    BRENDAi2.3.1.31. 2529.
    UniPathwayiUPA00051; UER00074.

    Protein family/group databases

    ESTHERihaein-metx. Homoserine_transacetylase.

    Names & Taxonomyi

    Protein namesi
    Recommended name:
    Homoserine O-acetyltransferaseUniRule annotationCurated (EC:2.3.1.31UniRule annotation2 Publications)
    Short name:
    HAT1 PublicationUniRule annotation
    Alternative name(s):
    Homoserine O-trans-acetylaseCurated
    Homoserine transacetylase1 PublicationUniRule annotation
    Short name:
    HTAUniRule annotationCurated
    Gene namesi
    Name:metXA1 PublicationUniRule annotation
    Synonyms:met2
    Ordered Locus Names:HI_1263
    OrganismiHaemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)
    Taxonomic identifieri71421 [NCBI]
    Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaPasteurellalesPasteurellaceaeHaemophilus
    Proteomesi
    • UP000000579 Componenti: Chromosome

    Subcellular locationi

    • Cytoplasm UniRule annotation

    GO - Cellular componenti

    Keywords - Cellular componenti

    Cytoplasm

    Pathology & Biotechi

    Mutagenesis

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Mutagenesisi306L → R: Can no longer use acetyl-CoA as acyl donor, but can use succinyl-CoA. 1 Publication1

    PTM / Processingi

    Molecule processing

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Initiator methionineiRemoved1 Publication
    ChainiPRO_00001557192 – 358Homoserine O-acetyltransferaseAdd BLAST357

    Interactioni

    Subunit structurei

    Homodimer.UniRule annotation2 Publications

    Protein-protein interaction databases

    STRINGi71421.HI1263.

    Structurei

    Secondary structure

    1358
    Legend: HelixTurnBeta strandPDB Structure known for this area
    Show more details
    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Beta strandi4 – 12Combined sources9
    Beta strandi24 – 33Combined sources10
    Beta strandi42 – 46Combined sources5
    Beta strandi58 – 60Combined sources3
    Helixi66 – 68Combined sources3
    Beta strandi73 – 76Combined sources4
    Turni77 – 79Combined sources3
    Beta strandi81 – 85Combined sources5
    Beta strandi91 – 95Combined sources5
    Turni102 – 104Combined sources3
    Beta strandi105 – 107Combined sources3
    Helixi109 – 111Combined sources3
    Helixi117 – 130Combined sources14
    Beta strandi136 – 142Combined sources7
    Helixi144 – 155Combined sources12
    Beta strandi159 – 167Combined sources9
    Helixi174 – 188Combined sources15
    Helixi194 – 196Combined sources3
    Helixi205 – 219Combined sources15
    Helixi222 – 228Combined sources7
    Turni229 – 231Combined sources3
    Helixi245 – 258Combined sources14
    Helixi263 – 275Combined sources13
    Turni278 – 281Combined sources4
    Helixi285 – 289Combined sources5
    Beta strandi294 – 301Combined sources8
    Beta strandi305 – 307Combined sources3
    Helixi309 – 321Combined sources13
    Beta strandi325 – 331Combined sources7
    Helixi336 – 338Combined sources3
    Helixi339 – 342Combined sources4
    Helixi344 – 356Combined sources13

    3D structure databases

    Select the link destinations:
    PDBei
    RCSB PDBi
    PDBji
    Links Updated
    PDB entryMethodResolution (Å)ChainPositionsPDBsum
    2B61X-ray1.65A1-358[»]
    ProteinModelPortaliP45131.
    SMRiP45131.
    ModBaseiSearch...
    MobiDBiSearch...

    Miscellaneous databases

    EvolutionaryTraceiP45131.

    Family & Domainsi

    Domains and Repeats

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Domaini41 – 343AB hydrolase-1UniRule annotationAdd BLAST303

    Sequence similaritiesi

    Belongs to the AB hydrolase superfamily. MetX family.UniRule annotation

    Phylogenomic databases

    eggNOGiENOG4105DWV. Bacteria.
    COG2021. LUCA.
    KOiK00641.
    OMAiCQGTTGP.
    PhylomeDBiP45131.

    Family and domain databases

    Gene3Di3.40.50.1820. 1 hit.
    HAMAPiMF_00296. MetX_acyltransf. 1 hit.
    InterProiView protein in InterPro
    IPR029058. AB_hydrolase.
    IPR000073. AB_hydrolase_1.
    IPR008220. Homoser/ser_AcTrfase.
    IPR034387. Homoser_AcTrfase.
    PfamiView protein in Pfam
    PF00561. Abhydrolase_1. 1 hit.
    PIRSFiPIRSF000443. Homoser_Ac_trans. 1 hit.
    SUPFAMiSSF53474. SSF53474. 1 hit.
    TIGRFAMsiTIGR01392. homoserO_Ac_trn. 1 hit.

    Sequencei

    Sequence statusi: Complete.

    Sequence processingi: The displayed sequence is further processed into a mature form.

    P45131-1 [UniParc]FASTAAdd to basket

    « Hide

            10         20         30         40         50
    MSVQNVVLFD TQPLTLMLGG KLSHINVAYQ TYGTLNAEKN NAVLICHALT
    60 70 80 90 100
    GDAEPYFDDG RDGWWQNFMG AGLALDTDRY FFISSNVLGG CKGTTGPSSI
    110 120 130 140 150
    NPQTGKPYGS QFPNIVVQDI VKVQKALLDH LGISHLKAII GGSFGGMQAN
    160 170 180 190 200
    QWAIDYPDFM DNIVNLCSSI YFSAEAIGFN HVMRQAVIND PNFNGGDYYE
    210 220 230 240 250
    GTPPDQGLSI ARMLGMLTYR TDLQLAKAFG RATKSDGSFW GDYFQVESYL
    260 270 280 290 300
    SYQGKKFLER FDANSYLHLL RALDMYDPSL GYDNVKEALS RIKARYTLVS
    310 320 330 340 350
    VTTDQLFKPI DLYKSKQLLE QSGVDLHFYE FPSDYGHDAF LVDYDQFEKR

    IRDGLAGN
    Length:358
    Mass (Da):39,990
    Last modified:January 23, 2007 - v3
    Checksum:i2484D6BEAC761983
    GO

    Mass spectrometryi

    Molecular mass is 39859 Da from positions 2 - 358. Determined by ESI. 1 Publication

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    L42023 Genomic DNA. Translation: AAC22916.1.
    PIRiD64113.
    RefSeqiNP_439418.1. NC_000907.1.
    WP_005694320.1. NC_000907.1.

    Genome annotation databases

    EnsemblBacteriaiAAC22916; AAC22916; HI_1263.
    GeneIDi950208.
    KEGGihin:HI1263.
    PATRICifig|71421.8.peg.1315.

    Similar proteinsi

    Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
    100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
    90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
    50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.

    Entry informationi

    Entry nameiMETXA_HAEIN
    AccessioniPrimary (citable) accession number: P45131
    Entry historyiIntegrated into UniProtKB/Swiss-Prot: November 1, 1995
    Last sequence update: January 23, 2007
    Last modified: June 7, 2017
    This is version 130 of the entry and version 3 of the sequence. See complete history.
    Entry statusiReviewed (UniProtKB/Swiss-Prot)
    Annotation programProkaryotic Protein Annotation Program

    Miscellaneousi

    Keywords - Technical termi

    3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

    Documents

    1. Haemophilus influenzae
      Haemophilus influenzae (strain Rd): entries and gene names
    2. PATHWAY comments
      Index of metabolic and biosynthesis pathways
    3. PDB cross-references
      Index of Protein Data Bank (PDB) cross-references
    4. SIMILARITY comments
      Index of protein domains and families