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Protein

Spermidine N(1)-acetyltransferase

Gene

speG

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

Functioni

Involved in the protection against polyamine toxicity by regulating their concentration (PubMed:7642535, PubMed:10986239). Catalyzes the transfer of an acetyl group from acetyl coenzyme A (AcCoA) to the primary amino groups of spermidine to yield N1- and N8-acetylspermidine (PubMed:8077207, PubMed:7052085, PubMed:6297970). It can also use polyamines such as spermine, but not putrescine (PubMed:7052085).5 Publications

Miscellaneous

Acetylation neutralizes the charge of the polyamine, which is then typically excreted from the cell.1 Publication

Catalytic activityi

Acetyl-CoA + an alkane-alpha,omega-diamine = CoA + an N-acetyldiamine.2 Publications

Enzyme regulationi

Heat shock, alkaline shift, ethanol treatment and poor nutrient availability produce increased concentrations of monoacetylated spermidine (PubMed:2061318). Inhibited by alkaline phosphatase, N1,N8-bis(ethyl)spermidine (BESPD) and N1,N(12)-bis(ethyl)spermidine (BESPM) (PubMed:8077207, PubMed:6297970).3 Publications

Kineticsi

  1. KM=2 µM for AcCoA (in the presence of 3 mM spermidine at pH 7.5 and 37 degrees Celsius)1 Publication
  2. KM=220 µM for spermine (in the presence of 10 µM AcCoA at pH 7.5 and 37 degrees Celsius)1 Publication
  3. KM=1290 µM for spermidine (in the presence of 10 µM AcCoA at pH 7.5 and 37 degrees Celsius)1 Publication

    Temperature dependencei

    The level of spermidine acetyltransferase activity increases at low temperature to prevent spermidine toxicity.1 Publication

    Sites

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Metal bindingi35Magnesium1 Publication1
    Binding sitei43SubstrateBy similarity1
    Metal bindingi76Magnesium1 Publication1
    Sitei85Could be important for selectivity toward long polyaminesBy similarity1

    GO - Molecular functioni

    • diamine N-acetyltransferase activity Source: UniProtKB
    • identical protein binding Source: EcoCyc
    • magnesium ion binding Source: UniProtKB

    GO - Biological processi

    • polyamine catabolic process Source: UniProtKB
    • protein homotetramerization Source: EcoCyc

    Keywordsi

    Molecular functionAcyltransferase, Transferase
    LigandMagnesium, Metal-binding

    Enzyme and pathway databases

    BioCyciEcoCyc:SPERMACTRAN-MONOMER
    MetaCyc:SPERMACTRAN-MONOMER

    Names & Taxonomyi

    Protein namesi
    Recommended name:
    Spermidine N(1)-acetyltransferase1 Publication (EC:2.3.1.572 Publications)
    Short name:
    SAT1 Publication
    Alternative name(s):
    Spermidine/spermine N(1)-acetyltransferase1 Publication
    Short name:
    SSAT1 Publication
    Gene namesi
    Name:speG
    Ordered Locus Names:b1584, JW1576
    OrganismiEscherichia coli (strain K12)
    Taxonomic identifieri83333 [NCBI]
    Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
    Proteomesi
    • UP000000318 Componenti: Chromosome
    • UP000000625 Componenti: Chromosome

    Organism-specific databases

    EcoGeneiEG12447 speG

    Subcellular locationi

    GO - Cellular componenti

    Keywords - Cellular componenti

    Cytoplasm

    Pathology & Biotechi

    Disruption phenotypei

    Cells lacking this gene accumulate spermidine at late stationary phase and show a reduced cell viability due to a decrease in protein biosynthesis (PubMed:7642535). At 37 degrees Celsius, growth of mutant is normal in the presence of 0.5 or 1 mM spermidine. However, following a shift to 7 degrees Celsius, the addition of 0.5 or 1 mM spermidine results in inhibition of cellular growth or cell lysis, respectively. Furthermore, at 7 degrees Celsius, spermidine accumulation resulted in a decrease in total protein synthesis accompanied by an increase in the synthesis of the major cold shock proteins CspA, CspB, and CspG (PubMed:10986239).2 Publications

    PTM / Processingi

    Molecule processing

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Initiator methionineiRemoved1 Publication
    ChainiPRO_00000745882 – 186Spermidine N(1)-acetyltransferaseAdd BLAST185

    Proteomic databases

    PaxDbiP0A951
    PRIDEiP0A951

    Expressioni

    Inductioni

    Constitutively expressed throughout log and plateau phases of growth.1 Publication

    Interactioni

    Subunit structurei

    Homotetramer.2 Publications

    GO - Molecular functioni

    • identical protein binding Source: EcoCyc

    Protein-protein interaction databases

    BioGridi4260234, 7 interactors
    ComplexPortaliCPX-2133 Diamine N-acetyltransferase complex
    IntActiP0A951, 11 interactors
    STRINGi316385.ECDH10B_1717

    Structurei

    Secondary structure

    1186
    Legend: HelixTurnBeta strandPDB Structure known for this area
    Show more details
    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Beta strandi7 – 11Combined sources5
    Helixi14 – 16Combined sources3
    Helixi17 – 21Combined sources5
    Beta strandi31 – 33Combined sources3
    Beta strandi36 – 38Combined sources3
    Helixi41 – 50Combined sources10
    Turni51 – 53Combined sources3
    Beta strandi58 – 64Combined sources7
    Beta strandi67 – 78Combined sources12
    Turni79 – 82Combined sources4
    Beta strandi83 – 90Combined sources8
    Helixi92 – 94Combined sources3
    Helixi99 – 113Combined sources15
    Beta strandi118 – 125Combined sources8
    Helixi129 – 137Combined sources9
    Beta strandi141 – 151Combined sources11
    Beta strandi153 – 165Combined sources13
    Helixi166 – 171Combined sources6

    3D structure databases

    Select the link destinations:
    PDBei
    RCSB PDBi
    PDBji
    Links Updated
    PDB entryMethodResolution (Å)ChainPositionsPDBsum
    4R9MX-ray2.90A/B/C1-186[»]
    6CY6X-ray1.75A1-186[»]
    ProteinModelPortaliP0A951
    SMRiP0A951
    ModBaseiSearch...
    MobiDBiSearch...

    Family & Domainsi

    Domains and Repeats

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Domaini7 – 167N-acetyltransferasePROSITE-ProRule annotationAdd BLAST161

    Region

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Regioni85 – 87Substrate bindingBy similarity3

    Sequence similaritiesi

    Belongs to the acetyltransferase family.Curated

    Phylogenomic databases

    eggNOGiENOG4108MK9 Bacteria
    COG1670 LUCA
    HOGENOMiHOG000078522
    InParanoidiP0A951
    KOiK00657
    OMAiTEIQIII
    PhylomeDBiP0A951

    Family and domain databases

    InterProiView protein in InterPro
    IPR016181 Acyl_CoA_acyltransferase
    IPR000182 GNAT_dom
    PfamiView protein in Pfam
    PF13302 Acetyltransf_3, 1 hit
    SUPFAMiSSF55729 SSF55729, 1 hit
    PROSITEiView protein in PROSITE
    PS51186 GNAT, 1 hit

    Sequencei

    Sequence statusi: Complete.

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

    P0A951-1 [UniParc]FASTAAdd to basket

    « Hide

            10         20         30         40         50
    MPSAHSVKLR PLEREDLRYV HQLDNNASVM RYWFEEPYEA FVELSDLYDK
    60 70 80 90 100
    HIHDQSERRF VVECDGEKAG LVELVEINHV HRRAEFQIII SPEYQGKGLA
    110 120 130 140 150
    TRAAKLAMDY GFTVLNLYKL YLIVDKENEK AIHIYRKLGF SVEGELMHEF
    160 170 180
    FINGQYRNAI RMCIFQHQYL AEHKTPGQTL LKPTAQ
    Length:186
    Mass (Da):21,887
    Last modified:January 23, 2007 - v2
    Checksum:i27297083B93B3752
    GO

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    D25276 Genomic DNA Translation: BAA04966.1
    U00096 Genomic DNA Translation: AAC74656.1
    AP009048 Genomic DNA Translation: BAA15286.1
    PIRiA55345
    RefSeqiNP_416101.1, NC_000913.3
    WP_001138581.1, NZ_LN832404.1

    Genome annotation databases

    EnsemblBacteriaiAAC74656; AAC74656; b1584
    BAA15286; BAA15286; BAA15286
    GeneIDi946117
    KEGGiecj:JW1576
    eco:b1584
    PATRICifig|1411691.4.peg.678

    Similar proteinsi

    Entry informationi

    Entry nameiATDA_ECOLI
    AccessioniPrimary (citable) accession number: P0A951
    Secondary accession number(s): P37354
    Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 19, 2005
    Last sequence update: January 23, 2007
    Last modified: June 20, 2018
    This is version 101 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

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

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