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Protein

Homoserine kinase

Gene

thrB

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: -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-KW
    • 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

    Keywordsi

    Molecular functionKinase, Transferase
    Biological processAmino-acid biosynthesis, Threonine biosynthesis
    LigandATP-binding, Nucleotide-binding

    Enzyme and pathway databases

    BioCyciEcoCyc:HOMOSERKIN-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

    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-2DPAGEiP00547

    Interactioni

    Protein-protein interaction databases

    BioGridi4261934, 9 interactors
    IntActiP00547, 2 interactors
    STRINGi316385.ECDH10B_0003

    Chemistry databases

    BindingDBiP00547

    Structurei

    3D structure databases

    ProteinModelPortaliP00547
    SMRiP00547
    ModBaseiSearch...
    MobiDBiSearch...

    Family & Domainsi

    Sequence similaritiesi

    Phylogenomic databases

    eggNOGiENOG4105D5I Bacteria
    COG0083 LUCA
    HOGENOMiHOG000247198
    InParanoidiP00547
    KOiK00872
    OMAiPDNVAPC
    PhylomeDBiP00547

    Family and domain databases

    Gene3Di3.30.230.10, 1 hit
    3.30.70.890, 1 hit
    HAMAPiMF_00384 Homoser_kinase, 1 hit
    InterProiView protein in InterPro
    IPR013750 GHMP_kinase_C_dom
    IPR036554 GHMP_kinase_C_sf
    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
    PANTHERiPTHR20861:SF1 PTHR20861:SF1, 1 hit
    PfamiView protein in Pfam
    PF08544 GHMP_kinases_C, 1 hit
    PF00288 GHMP_kinases_N, 1 hit
    PIRSFiPIRSF000676 Homoser_kin, 1 hit
    SUPFAMiSSF54211 SSF54211, 1 hit
    SSF55060 SSF55060, 1 hit
    TIGRFAMsiTIGR00191 thrB, 1 hit
    PROSITEiView protein in PROSITE
    PS00627 GHMP_KINASES_ATP, 1 hit

    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
    PATRICifig|1411691.4.peg.2280

    Similar proteinsi

    Entry informationi

    Entry nameiKHSE_ECOLI
    AccessioniPrimary (citable) accession number: P00547
    Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 21, 1986
    Last sequence update: April 1, 1993
    Last modified: March 28, 2018
    This is version 152 of the entry and version 2 of the sequence. See complete history.
    Entry statusiReviewed (UniProtKB/Swiss-Prot)
    Annotation programProkaryotic Protein Annotation Program

    Miscellaneousi

    Keywords - Technical termi

    Complete proteome, Reference proteome
    UniProt is an ELIXIR core data resource
    Main funding by: National Institutes of Health