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Protein

Homoserine kinase

Gene

HSK

Organism
Arabidopsis thaliana (Mouse-ear cress)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

Catalyzes the ATP-dependent phosphorylation of L-homoserine to L-homoserine phosphate. Is specific for L-homoserine and cannot use other substrates such D-serine, L-serine, D-threonine and L-threonine, galactose or D-homoserine in vitro. Required for susceptibility to the downy mildew pathogen Hyaloperonospora parasitica.4 Publications

Catalytic activityi

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

Kineticsi

  1. KM=0.40 mM for L-homoserine1 Publication
  2. KM=0.32 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. AK1 (AXX17_At5g12690), Aspartokinase 2, chloroplastic (AK2), Aspartokinase (AXX17_At5g13510), Aspartokinase 1, chloroplastic (AK1), Aspartokinase (CARAB-AK-LYS), Aspartokinase 3, chloroplastic (AK3), Aspartokinase (AXX17_At3g01160), Bifunctional aspartokinase/homoserine dehydrogenase 2, chloroplastic (AKHSDH2), Aspartokinase (AXX17_At3g01160), Aspartokinase (AXX17_At3g01160), Bifunctional aspartokinase/homoserine dehydrogenase 1, chloroplastic (AKHSDH1)
    2. no protein annotated in this organism
    3. Homoserine dehydrogenase (AXX17_At5g21030), Homoserine dehydrogenase (At5g21060), Homoserine dehydrogenase (AXX17_At5g21030), Homoserine dehydrogenase (At5g21060), Homoserine dehydrogenase, Homoserine dehydrogenase (At5g21060), Bifunctional aspartokinase/homoserine dehydrogenase 2, chloroplastic (AKHSDH2), Bifunctional aspartokinase/homoserine dehydrogenase 1, chloroplastic (AKHSDH1)
    4. Homoserine kinase (HSK)
    5. Threonine synthase 2, chloroplastic (TS2), Threonine synthase 1, chloroplastic (TS1)
    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 bindingi143 – 154ATPSequence analysisAdd BLAST12

    GO - Molecular functioni

    • ATP binding Source: UniProtKB-KW
    • homoserine kinase activity Source: TAIR

    GO - Biological processi

    • defense response Source: UniProtKB-KW
    • homoserine metabolic process Source: GO_Central
    • methionine biosynthetic process Source: TAIR
    • response to bacterium Source: TAIR
    • response to fungus Source: TAIR
    • threonine biosynthetic process Source: TAIR

    Keywordsi

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

    Enzyme and pathway databases

    BioCyciMetaCyc:MONOMER-1961
    BRENDAi2.7.1.39 399
    SABIO-RKiQ8L7R2
    UniPathwayiUPA00050; UER00064

    Names & Taxonomyi

    Protein namesi
    Recommended name:
    Homoserine kinase (EC:2.7.1.39)
    Alternative name(s):
    Protein DOWNY MILDEW RESISTANT 1
    Gene namesi
    Name:HSK
    Synonyms:DMR1
    Ordered Locus Names:At2g17265
    ORF Names:F5J6.24
    OrganismiArabidopsis thaliana (Mouse-ear cress)
    Taxonomic identifieri3702 [NCBI]
    Taxonomic lineageiEukaryotaViridiplantaeStreptophytaEmbryophytaTracheophytaSpermatophytaMagnoliophytaeudicotyledonsGunneridaePentapetalaerosidsmalvidsBrassicalesBrassicaceaeCamelineaeArabidopsis
    Proteomesi
    • UP000006548 Componenti: Chromosome 2

    Organism-specific databases

    AraportiAT2G17265
    TAIRilocus:2827533 AT2G17265

    Subcellular locationi

    Extracellular region or secreted Cytosol Plasma membrane Cell wall Cytoskeleton Vacuole Chloroplast Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertion Graphics by Christian Stolte; Source: COMPARTMENTS

    Keywords - Cellular componenti

    Chloroplast, Plastid

    Pathology & Biotechi

    Disruption phenotypei

    No visible phenotype under normal growth conditions, but mutant plant accumulate homoserine and show reduced susceptibility to the downy mildew pathogen Hyaloperonospora parasitica.3 Publications

    Mutagenesis

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Mutagenesisi46E → K in dmr1-2; loss of function. 1 Publication1
    Mutagenesisi118G → R in dmr1-6; loss of function. 1 Publication1
    Mutagenesisi180G → D in dmr1-5; loss of function. 1 Publication1
    Mutagenesisi202G → R in dmr1-4; loss of function. 1 Publication1
    Mutagenesisi241M → K in dmr1-3; loss of function. 1 Publication1
    Mutagenesisi267A → V in dmr1-1; loss of function. 1 Publication1

    PTM / Processingi

    Molecule processing

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Transit peptidei1 – 34ChloroplastSequence analysisAdd BLAST34
    ChainiPRO_000042866235 – 370Homoserine kinaseAdd BLAST336

    Proteomic databases

    PaxDbiQ8L7R2
    PRIDEiQ8L7R2
    ProMEXiQ8L7R2

    Expressioni

    Gene expression databases

    ExpressionAtlasiQ8L7R2 baseline and differential
    GenevisibleiQ8L7R2 AT

    Interactioni

    Protein-protein interaction databases

    STRINGi3702.AT2G17265.1

    Structurei

    3D structure databases

    ProteinModelPortaliQ8L7R2
    SMRiQ8L7R2
    ModBaseiSearch...
    MobiDBiSearch...

    Family & Domainsi

    Compositional bias

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Compositional biasi153 – 162Poly-Ala10

    Sequence similaritiesi

    Keywords - Domaini

    Transit peptide

    Phylogenomic databases

    eggNOGiKOG1537 Eukaryota
    COG0083 LUCA
    HOGENOMiHOG000247197
    InParanoidiQ8L7R2
    KOiK00872
    OMAiPDNVAPC
    OrthoDBiEOG09360E8Z
    PhylomeDBiQ8L7R2

    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
    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.

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

    Q8L7R2-1 [UniParc]FASTAAdd to basket

    « Hide

            10         20         30         40         50
    MASLCFQSPS KPISYFQPKS NPSPPLFAKV SVFRCRASVQ TLVAVEPEPV
    60 70 80 90 100
    FVSVKTFAPA TVANLGPGFD FLGCAVDGLG DHVTLRVDPS VRAGEVSISE
    110 120 130 140 150
    ITGTTTKLST NPLRNCAGIA AIATMKMLGI RSVGLSLDLH KGLPLGSGLG
    160 170 180 190 200
    SSAASAAAAA VAVNEIFGRK LGSDQLVLAG LESEAKVSGY HADNIAPAIM
    210 220 230 240 250
    GGFVLIRNYE PLDLKPLRFP SDKDLFFVLV SPDFEAPTKK MRAALPTEIP
    260 270 280 290 300
    MVHHVWNSSQ AAALVAAVLE GDAVMLGKAL SSDKIVEPTR APLIPGMEAV
    310 320 330 340 350
    KKAALEAGAF GCTISGAGPT AVAVIDSEEK GQVIGEKMVE AFWKVGHLKS
    360 370
    VASVKKLDNV GARLVNSVSR
    Length:370
    Mass (Da):38,529
    Last modified:October 1, 2002 - v1
    Checksum:i50FB7315AF061889
    GO

    Experimental Info

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Sequence conflicti32V → F in BAC42512 (PubMed:11910074).Curated1
    Sequence conflicti218R → K in AAD33097 (PubMed:10562426).Curated1
    Sequence conflicti233D → E in AAD33097 (PubMed:10562426).Curated1
    Sequence conflicti359N → K in AAD33097 (PubMed:10562426).Curated1

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    AF082525 mRNA Translation: AAD33097.1
    CP002685 Genomic DNA Translation: AEC06605.1
    AK117871 mRNA Translation: BAC42512.2
    AY128313 mRNA Translation: AAM91516.1
    BT001174 mRNA Translation: AAN65061.1
    RefSeqiNP_179318.1, NM_127281.2
    UniGeneiAt.10492
    At.26823

    Genome annotation databases

    EnsemblPlantsiAT2G17265.1; AT2G17265.1; AT2G17265
    GeneIDi816232
    GrameneiAT2G17265.1; AT2G17265.1; AT2G17265
    KEGGiath:AT2G17265

    Similar proteinsi

    Entry informationi

    Entry nameiKHSE_ARATH
    AccessioniPrimary (citable) accession number: Q8L7R2
    Secondary accession number(s): Q7FLV1, Q9XEE0
    Entry historyiIntegrated into UniProtKB/Swiss-Prot: April 16, 2014
    Last sequence update: October 1, 2002
    Last modified: April 25, 2018
    This is version 126 of the entry and version 1 of the sequence. See complete history.
    Entry statusiReviewed (UniProtKB/Swiss-Prot)
    Annotation programPlant 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