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Protein

Homoserine kinase

Gene

thrB

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: Annotation score: 4 out of 5-Experimental evidence at protein leveli

Functioni

Catalyzes the ATP-dependent phosphorylation of L-homoserine to L-homoserine phosphate. Is also able to phosphorylate the hydroxy group on gamma-carbon of L-homoserine analogs when the functional group at the alpha-position is a carboxyl, an ester, or even a hydroxymethyl group. Neither L-threonine nor L-serine are substrates of the enzyme.1 Publication

Catalytic activityi

ATP + L-homoserine = ADP + O-phospho-L-homoserine.1 Publication

Kineticsi

The catalytic efficiency is 500-fold higher with L-homoserine than with D-homoserine as substrate.

  1. KM=0.14 mM for L-homoserine1 Publication
  2. KM=31.8 mM for D-homoserine1 Publication
  3. KM=0.13 mM for ATP1 Publication

    Pathwayi: L-threonine biosynthesis

    This protein is involved in step 4 of the subpathway that synthesizes L-threonine from L-aspartate.
    Proteins known to be involved in the 5 steps of the subpathway in this organism are:
    1. Bifunctional aspartokinase/homoserine dehydrogenase 1 (thrA), Bifunctional aspartokinase/homoserine dehydrogenase 2 (metL)
    2. Aspartate-semialdehyde dehydrogenase (asd)
    3. Bifunctional aspartokinase/homoserine dehydrogenase 1 (thrA), Bifunctional aspartokinase/homoserine dehydrogenase 2 (metL)
    4. Homoserine kinase (thrB)
    5. Threonine synthase (thrC)
    This subpathway is part of the pathway L-threonine biosynthesis, 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 L-threonine from L-aspartate, the pathway L-threonine biosynthesis and in Amino-acid biosynthesis.

    Regions

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Nucleotide bindingi91 – 101ATPSequence analysisAdd BLAST11

    GO - Molecular functioni

    • ATP binding Source: UniProtKB-HAMAP
    • homoserine kinase activity Source: EcoCyc

    GO - Biological processi

    • homoserine metabolic process Source: GO_Central
    • methionine biosynthetic process Source: GO_Central
    • threonine biosynthetic process Source: EcoCyc
    Complete GO annotation...

    Keywords - Molecular functioni

    Kinase, Transferase

    Keywords - Biological processi

    Amino-acid biosynthesis, Threonine biosynthesis

    Keywords - Ligandi

    ATP-binding, Nucleotide-binding

    Enzyme and pathway databases

    BioCyciEcoCyc:HOMOSERKIN-MONOMER.
    ECOL316407:JW0002-MONOMER.
    MetaCyc:HOMOSERKIN-MONOMER.
    UniPathwayiUPA00050; UER00064.

    Names & Taxonomyi

    Protein namesi
    Recommended name:
    Homoserine kinase (EC:2.7.1.39)
    Short name:
    HK
    Short name:
    HSK
    Gene namesi
    Name:thrB
    Ordered Locus Names:b0003, JW0002
    OrganismiEscherichia coli (strain K12)
    Taxonomic identifieri83333 [NCBI]
    Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
    Proteomesi
    • UP000000318 Componenti: Chromosome
    • UP000000625 Componenti: Chromosome

    Organism-specific databases

    EcoGeneiEG10999. thrB.

    Subcellular locationi

    GO - Cellular componenti

    • cytosol Source: EcoCyc
    Complete GO annotation...

    Keywords - Cellular componenti

    Cytoplasm

    Pathology & Biotechi

    Mutagenesis

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Mutagenesisi139H → L: 35-fold decrease in kinase activity. 1 Publication1
    Mutagenesisi203H → L: 2-fold decrease in kinase activity but nearly no change in substrates affinity. 1 Publication1
    Mutagenesisi206H → Q: 3500-fold decrease in kinase activity. 1 Publication1
    Mutagenesisi235R → H: 250-fold decrease in kinase activity but no change in substrates affinity. 1 Publication1
    Mutagenesisi235R → L: 26200-fold decrease in catalytic efficiency. 1 Publication1

    PTM / Processingi

    Molecule processing

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    ChainiPRO_00001565671 – 310Homoserine kinaseAdd BLAST310

    Proteomic databases

    PaxDbiP00547.
    PRIDEiP00547.

    2D gel databases

    SWISS-2DPAGEP00547.

    Interactioni

    Protein-protein interaction databases

    BioGridi4261934. 5 interactors.
    IntActiP00547. 2 interactors.
    STRINGi511145.b0003.

    Chemistry databases

    BindingDBiP00547.

    Structurei

    3D structure databases

    ProteinModelPortaliP00547.
    SMRiP00547.
    ModBaseiSearch...
    MobiDBiSearch...

    Family & Domainsi

    Sequence similaritiesi

    Phylogenomic databases

    eggNOGiENOG4105D5I. Bacteria.
    COG0083. LUCA.
    HOGENOMiHOG000247198.
    InParanoidiP00547.
    KOiK00872.
    OMAiFVHICKV.
    PhylomeDBiP00547.

    Family and domain databases

    Gene3Di3.30.230.10. 1 hit.
    3.30.70.890. 1 hit.
    HAMAPiMF_00384. Homoser_kinase. 1 hit.
    InterProiIPR013750. GHMP_kinase_C_dom.
    IPR006204. GHMP_kinase_N_dom.
    IPR006203. GHMP_knse_ATP-bd_CS.
    IPR000870. Homoserine_kinase.
    IPR020568. Ribosomal_S5_D2-typ_fold.
    IPR014721. Ribosomal_S5_D2-typ_fold_subgr.
    [Graphical view]
    PfamiPF08544. GHMP_kinases_C. 1 hit.
    PF00288. GHMP_kinases_N. 1 hit.
    [Graphical view]
    PIRSFiPIRSF000676. Homoser_kin. 1 hit.
    SUPFAMiSSF54211. SSF54211. 1 hit.
    SSF55060. SSF55060. 1 hit.
    TIGRFAMsiTIGR00191. thrB. 1 hit.
    PROSITEiPS00627. GHMP_KINASES_ATP. 1 hit.
    [Graphical view]

    Sequencei

    Sequence statusi: Complete.

    P00547-1 [UniParc]FASTAAdd to basket

    « Hide

            10         20         30         40         50
    MVKVYAPASS ANMSVGFDVL GAAVTPVDGA LLGDVVTVEA AETFSLNNLG
    60 70 80 90 100
    RFADKLPSEP RENIVYQCWE RFCQELGKQI PVAMTLEKNM PIGSGLGSSA
    110 120 130 140 150
    CSVVAALMAM NEHCGKPLND TRLLALMGEL EGRISGSIHY DNVAPCFLGG
    160 170 180 190 200
    MQLMIEENDI ISQQVPGFDE WLWVLAYPGI KVSTAEARAI LPAQYRRQDC
    210 220 230 240 250
    IAHGRHLAGF IHACYSRQPE LAAKLMKDVI AEPYRERLLP GFRQARQAVA
    260 270 280 290 300
    EIGAVASGIS GSGPTLFALC DKPETAQRVA DWLGKNYLQN QEGFVHICRL
    310
    DTAGARVLEN
    Length:310
    Mass (Da):33,624
    Last modified:April 1, 1993 - v2
    Checksum:i0F225F9F1B634BE8
    GO

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    L13601 Genomic DNA. Translation: AAA20618.1.
    U14003 Genomic DNA. Translation: AAA97302.1.
    U00096 Genomic DNA. Translation: AAC73114.1.
    AP009048 Genomic DNA. Translation: BAB96580.2.
    PIRiS56630. KIECM.
    RefSeqiNP_414544.1. NC_000913.3.
    WP_000241662.1. NZ_LN832404.1.

    Genome annotation databases

    EnsemblBacteriaiAAC73114; AAC73114; b0003.
    BAB96580; BAB96580; BAB96580.
    GeneIDi947498.
    KEGGiecj:JW0002.
    eco:b0003.
    PATRICi32115101. VBIEscCol129921_0002.

    Cross-referencesi

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    L13601 Genomic DNA. Translation: AAA20618.1.
    U14003 Genomic DNA. Translation: AAA97302.1.
    U00096 Genomic DNA. Translation: AAC73114.1.
    AP009048 Genomic DNA. Translation: BAB96580.2.
    PIRiS56630. KIECM.
    RefSeqiNP_414544.1. NC_000913.3.
    WP_000241662.1. NZ_LN832404.1.

    3D structure databases

    ProteinModelPortaliP00547.
    SMRiP00547.
    ModBaseiSearch...
    MobiDBiSearch...

    Protein-protein interaction databases

    BioGridi4261934. 5 interactors.
    IntActiP00547. 2 interactors.
    STRINGi511145.b0003.

    Chemistry databases

    BindingDBiP00547.

    2D gel databases

    SWISS-2DPAGEP00547.

    Proteomic databases

    PaxDbiP00547.
    PRIDEiP00547.

    Protocols and materials databases

    Structural Biology KnowledgebaseSearch...

    Genome annotation databases

    EnsemblBacteriaiAAC73114; AAC73114; b0003.
    BAB96580; BAB96580; BAB96580.
    GeneIDi947498.
    KEGGiecj:JW0002.
    eco:b0003.
    PATRICi32115101. VBIEscCol129921_0002.

    Organism-specific databases

    EchoBASEiEB0992.
    EcoGeneiEG10999. thrB.

    Phylogenomic databases

    eggNOGiENOG4105D5I. Bacteria.
    COG0083. LUCA.
    HOGENOMiHOG000247198.
    InParanoidiP00547.
    KOiK00872.
    OMAiFVHICKV.
    PhylomeDBiP00547.

    Enzyme and pathway databases

    UniPathwayiUPA00050; UER00064.
    BioCyciEcoCyc:HOMOSERKIN-MONOMER.
    ECOL316407:JW0002-MONOMER.
    MetaCyc:HOMOSERKIN-MONOMER.

    Miscellaneous databases

    PROiP00547.

    Family and domain databases

    Gene3Di3.30.230.10. 1 hit.
    3.30.70.890. 1 hit.
    HAMAPiMF_00384. Homoser_kinase. 1 hit.
    InterProiIPR013750. GHMP_kinase_C_dom.
    IPR006204. GHMP_kinase_N_dom.
    IPR006203. GHMP_knse_ATP-bd_CS.
    IPR000870. Homoserine_kinase.
    IPR020568. Ribosomal_S5_D2-typ_fold.
    IPR014721. Ribosomal_S5_D2-typ_fold_subgr.
    [Graphical view]
    PfamiPF08544. GHMP_kinases_C. 1 hit.
    PF00288. GHMP_kinases_N. 1 hit.
    [Graphical view]
    PIRSFiPIRSF000676. Homoser_kin. 1 hit.
    SUPFAMiSSF54211. SSF54211. 1 hit.
    SSF55060. SSF55060. 1 hit.
    TIGRFAMsiTIGR00191. thrB. 1 hit.
    PROSITEiPS00627. GHMP_KINASES_ATP. 1 hit.
    [Graphical view]
    ProtoNetiSearch...

    Entry informationi

    Entry nameiKHSE_ECOLI
    AccessioniPrimary (citable) accession number: P00547
    Entry historyi
    Integrated into UniProtKB/Swiss-Prot: July 21, 1986
    Last sequence update: April 1, 1993
    Last modified: November 30, 2016
    This is version 146 of the entry and version 2 of the sequence. [Complete history]
    Entry statusiReviewed (UniProtKB/Swiss-Prot)
    Annotation programProkaryotic Protein Annotation Program

    Miscellaneousi

    Keywords - Technical termi

    Complete proteome, Reference proteome

    Documents

    1. Escherichia coli
      Escherichia coli (strain K12): entries and cross-references to EcoGene
    2. PATHWAY comments
      Index of metabolic and biosynthesis pathways
    3. SIMILARITY comments
      Index of protein domains and families

    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.