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Protein

GTPase ObgE/CgtA

Gene

obgE

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

Functioni

An abundant, essential GTPase which binds GTP, GDP and ppGpp with moderate affinity. Has high guanosine nucleotide exchange rate constants for GTP and GDP, and a relatively low GTP hydrolysis rate stimulated by the 50S ribosomal subunit. It is estimated there are 34000 molecules in log-phase cells and 5600 molecules in stationary-phase cells. Required for chromosome segregation. Plays a role in the stringent response, perhaps by sequestering 50S ribosomal subunits and decreasing protein synthesis (PubMed:19555460), and a non-essential role in the late steps of ribosome biogenesis, perhaps acting as a checkpoint for correct 50S subunit synthesis (Probable) (PubMed:24844575). Overexpression increases bacterial persistence (in exponential and stationary phase) in response to antibiotics (PubMed:26051177). Cells expressing high levels of Obg are more likely to form persister cells upon antibiotic exposure; this requires alarmone (p)ppGpp and acts via induced HokB, depolarizing cells, which probably reduces metabolic activity and induces persistence (PubMed:26051177). The persister phenotype can be separated from the essential phenotype (PubMed:26051177).1 Publication9 Publications
Required for correct chromosome partitioning; in temperature-sensitive (ts) mutant nucleoids do not partition but remain in the middle of cell, cells elongate but do not divide. Overexpression protects cells against UV damage. Ts mutants have impaired plasmid and lamdba phage replication, possibly via effects on DnaA (PubMed:12826057). Regulates DnaA levels. Genetic interactions of Val-168 and a C-terminal insertion mutant with the double-strand break repair factors recA and recBCD, and with seqA suggests that ObgE, either directly or indirectly, promotes replication fork stability (PubMed:15721258). May protect replication forks from stress induced by toxic levels of hydroxyl radicals (PubMed:22863262). Initiation of DNA replication continues in ObgE-depleted cells.8 Publications
Binds to pre-50S ribosomal subunits in a salt-dependent manner. Acts as a ribosome anti-association factor; guanosine nucleotides stimulate ObgE 50S subunit binding and also ObgE-mediated 70S ribosome dissocation (GDP<GTP<GMP-PNP<ppGpp) (PubMed:24844575). Overexpression rescues an rrmJ deletion stabilizing the 70S ribosome. Even at permissive temperatures the ts mutant (Gln-80/Asn-85) shows disrupted 50S ribosomal subunit assembly, defects in 16 and 23S rRNA processing and altered association of some late-assembling ribosomal proteins (PubMed:11555285). Dissociates from the pre-50S ribosome under conditions of amino acid starvation. The levels of (p)ppGpp rise in the ts mutant (Gln-80/Asn-85), possibly because ObgE controls SpoT. Binds GDP and ppGpp with the same affinity. During ribosome assembly ObgE acts later than the rRNA methyltransferase RrmJ and DEAD-box RNA helicases DeaD and SrmB.8 Publications

Cofactori

Mg2+UniRule annotation1 Publication

Kineticsi

Turnover number of 0.02/min.

  1. KM=18 µM for GTP (at 37 degrees Celsius2 Publications
  2. KM=7.9 µM for GTP (at 30 degrees Celsius2 Publications

    Sites

    Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
    Metal bindingi173 – 1731MagnesiumUniRule annotation
    Metal bindingi193 – 1931MagnesiumUniRule annotation

    Regions

    Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
    Nucleotide bindingi166 – 1738GTPUniRule annotation
    Nucleotide bindingi191 – 1955GTPUniRule annotation
    Nucleotide bindingi213 – 2164GTPUniRule annotation
    Nucleotide bindingi283 – 2864GTPUniRule annotation
    Nucleotide bindingi314 – 3163GTPUniRule annotation

    GO - Molecular functioni

    • DNA binding Source: UniProtKB-KW
    • GDP binding Source: EcoCyc
    • GTPase activity Source: EcoCyc
    • GTP binding Source: EcoCyc
    • guanyl ribonucleotide binding Source: EcoCyc
    • magnesium ion binding Source: UniProtKB-HAMAP
    • rRNA binding Source: UniProtKB-KW

    GO - Biological processi

    • chromosome segregation Source: EcoCyc
    • dormancy process Source: UniProtKB
    • ribosome assembly Source: EcoCyc
    Complete GO annotation...

    Keywords - Molecular functioni

    Hydrolase

    Keywords - Ligandi

    DNA-binding, GTP-binding, Magnesium, Metal-binding, Nucleotide-binding, RNA-binding, rRNA-binding

    Enzyme and pathway databases

    BioCyciEcoCyc:G7656-MONOMER.
    ECOL316407:JW3150-MONOMER.

    Names & Taxonomyi

    Protein namesi
    Recommended name:
    GTPase ObgE/CgtAUniRule annotation (EC:3.6.5.-UniRule annotation1 Publication)
    Alternative name(s):
    GTP-binding protein ObgUniRule annotation
    Gene namesi
    Name:obgE1 Publication
    Synonyms:cgtA1 Publication, obgUniRule annotation, yhbZ
    Ordered Locus Names:b3183, JW3150
    OrganismiEscherichia coli (strain K12)
    Taxonomic identifieri83333 [NCBI]
    Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacterialesEnterobacteriaceaeEscherichia
    Proteomesi
    • UP000000318 Componenti: Chromosome
    • UP000000625 Componenti: Chromosome

    Organism-specific databases

    EcoGeneiEG12795. obgE.

    Subcellular locationi

    GO - Cellular componenti

    • cytosol Source: EcoCyc
    Complete GO annotation...

    Keywords - Cellular componenti

    Cytoplasm

    Pathology & Biotechi

    Disruption phenotypei

    Essential for growth, it cannot be disrupted.1 Publication

    Mutagenesis

    Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
    Mutagenesisi27 – 315KYIPK → EYIPE: Almost abolishes 50S subunit binding. 1 Publication
    Mutagenesisi76 – 827RDCTGKR → GDCTGKG: Slight reduction in 50S subunit binding. 1 Publication
    Mutagenesisi80 – 801G → E: Temperature-sensitive for growth at 42 degrees Celsius, defects in chromosome partitioning; when associated with N-85. 1 Publication
    Mutagenesisi85 – 851D → N: Temperature-sensitive for growth at 42 degrees Celsius, defects in chromosome partitioning; when associated with E-80. 1 Publication
    Mutagenesisi93 – 931G → D: No effect on persister cell formation upon overexpression. 1 Publication
    Mutagenesisi136 – 1394RTPR → GTPG: Almost abolishes 50S subunit binding. 1 Publication
    Mutagenesisi159 – 1591L → Q: Increased sensitivity to HU upon overexpression, supports normal growth, no effect in mazEF/relBE or tonB deletions. 1 Publication
    Mutagenesisi163 – 1631G → V: Increased sensitivity to HU upon overexpression, supports normal growth, no effect in mazEF/relBE or tonB deletions. 1 Publication
    Mutagenesisi166 – 1661G → V: No increase in persister cells upon overexpression, does not induce hokB expression, supports normal growth. 1 Publication
    Mutagenesisi168 – 1681P → V: Increased sensitivity to HU upon overexpression, supports normal growth, no effect in mazEF/relBE or tonB deletions. No effect on persister cell formation upon overexpression. 3 Publications
    Mutagenesisi173 – 1731S → N: No effect on persister cell formation upon overexpression. 1 Publication
    Mutagenesisi193 – 1931T → A: No effect on persister cell formation upon overexpression. 1 Publication
    Mutagenesisi216 – 2161G → A: Increased sensitivity to HU upon overexpression, supports normal growth, no effect in mazEF/relBE or tonB deletions. No effect on persister cell formation upon overexpression. 2 Publications
    Mutagenesisi237 – 2371R → C: Increased sensitivity to HU upon overexpression, supports normal growth, no effect in mazEF/relBE or tonB deletions. 1 Publication
    Mutagenesisi314 – 3141S → P: Severe growth defect at 42 degrees Celsius. Decreased levels of some ribosomal proteins, altered PTMs of others. 1 Publication

    PTM / Processingi

    Molecule processing

    Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
    Chaini1 – 390390GTPase ObgE/CgtAPRO_0000205433Add
    BLAST

    Proteomic databases

    EPDiP42641.
    PaxDbiP42641.
    PRIDEiP42641.

    Expressioni

    Inductioni

    Constitutively expressed, levels decrease toward stationary phase (at protein level). Induced in a dose-dependent manner by UV irradiation.2 Publications

    Interactioni

    Subunit structurei

    Monomer. Binds to the intersubunit face of the 50S ribosomal subunit where translation factors bind, protruding into the peptidyl-transfer center, leading to significant changes in both ObgE and 50S ribosome structure (PubMed:24844575). Associates with SpoT (PubMed:15292126, PubMed:17616600). Binding to 50S ribosomes does not require SpoT. 50S ribosomal subunit binding is enhanced by guanosine nucleotides (PubMed:24844575).5 Publications

    Protein-protein interaction databases

    BioGridi4261647. 134 interactions.
    DIPiDIP-12273N.
    IntActiP42641. 28 interactions.
    MINTiMINT-1234247.
    STRINGi511145.b3183.

    Structurei

    3D structure databases

    Select the link destinations:
    PDBei
    RCSB PDBi
    PDBji
    Links Updated
    EntryMethodResolution (Å)ChainPositionsPDBsum
    4CSUelectron microscopy5.5091-390[»]
    ProteinModelPortaliP42641.
    SMRiP42641. Positions 4-336.
    ModBaseiSearch...
    MobiDBiSearch...

    Family & Domainsi

    Domains and Repeats

    Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
    Domaini160 – 333174OBG-type GUniRule annotationAdd
    BLAST

    Region

    Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
    Regioni341 – 39050Not required for 50S ribosome subunit association nor 70S dissociation1 PublicationAdd
    BLAST
    Regioni360 – 39031Not essential, but deletion increases sensitivity to DNA replication inhibitor hydroxyurea (HU)1 PublicationAdd
    BLAST

    Domaini

    The C-terminus (residues 341-390) is not required for either 50S ribosome subunit association nor 70S ribosome dissociation.1 Publication

    Sequence similaritiesi

    Belongs to the TRAFAC class OBG-HflX-like GTPase superfamily. OBG GTPase family.UniRule annotation
    Contains 1 OBG-type G (guanine nucleotide-binding) domain.UniRule annotation

    Phylogenomic databases

    eggNOGiENOG4105C9R. Bacteria.
    COG0536. LUCA.
    HOGENOMiHOG000019084.
    InParanoidiP42641.
    KOiK03979.
    OMAiLVDFRYK.
    PhylomeDBiP42641.

    Family and domain databases

    Gene3Di2.70.210.12. 1 hit.
    3.40.50.300. 1 hit.
    HAMAPiMF_01454. GTPase_Obg. 1 hit.
    InterProiIPR031167. G_OBG.
    IPR014100. GTP-bd_Obg/CgtA.
    IPR006074. GTP1-OBG_CS.
    IPR006169. GTP1_OBG_dom.
    IPR006073. GTP_binding_domain.
    IPR027417. P-loop_NTPase.
    [Graphical view]
    PANTHERiPTHR11702:SF3. PTHR11702:SF3. 1 hit.
    PfamiPF01018. GTP1_OBG. 1 hit.
    PF01926. MMR_HSR1. 1 hit.
    [Graphical view]
    PIRSFiPIRSF002401. GTP_bd_Obg/CgtA. 1 hit.
    PRINTSiPR00326. GTP1OBG.
    SUPFAMiSSF52540. SSF52540. 1 hit.
    SSF82051. SSF82051. 1 hit.
    TIGRFAMsiTIGR02729. Obg_CgtA. 1 hit.
    PROSITEiPS51710. G_OBG. 1 hit.
    PS00905. GTP1_OBG. 1 hit.
    [Graphical view]

    Sequencei

    Sequence statusi: Complete.

    P42641-1 [UniParc]FASTAAdd to basket

    « Hide

            10         20         30         40         50
    MKFVDEASIL VVAGDGGNGC VSFRREKYIP KGGPDGGDGG DGGDVWMEAD
    60 70 80 90 100
    ENLNTLIDYR FEKSFRAERG QNGASRDCTG KRGKDVTIKV PVGTRVIDQG
    110 120 130 140 150
    TGETMGDMTK HGQRLLVAKG GWHGLGNTRF KSSVNRTPRQ KTNGTPGDKR
    160 170 180 190 200
    ELLLELMLLA DVGMLGMPNA GKSTFIRAVS AAKPKVADYP FTTLVPSLGV
    210 220 230 240 250
    VRMDNEKSFV VADIPGLIEG AAEGAGLGIR FLKHLERCRV LLHLIDIDPI
    260 270 280 290 300
    DGTDPVENAR IIISELEKYS QDLATKPRWL VFNKIDLLDK VEAEEKAKAI
    310 320 330 340 350
    AEALGWEDKY YLISAASGLG VKDLCWDVMT FIIENPVVQA EEAKQPEKVE
    360 370 380 390
    FMWDDYHRQQ LEEIAEEDDE DWDDDWDEDD EEGVEFIYKR
    Length:390
    Mass (Da):43,286
    Last modified:November 1, 1995 - v1
    Checksum:i3A6EBF56F24B7C47
    GO

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    U18997 Genomic DNA. Translation: AAA57984.1.
    U00096 Genomic DNA. Translation: AAC76215.1.
    AP009048 Genomic DNA. Translation: BAE77227.1.
    PIRiA65109.
    RefSeqiNP_417650.1. NC_000913.3.
    WP_000673575.1. NZ_LN832404.1.

    Genome annotation databases

    EnsemblBacteriaiAAC76215; AAC76215; b3183.
    BAE77227; BAE77227; BAE77227.
    GeneIDi947694.
    KEGGiecj:JW3150.
    eco:b3183.
    PATRICi32121786. VBIEscCol129921_3277.

    Cross-referencesi

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    U18997 Genomic DNA. Translation: AAA57984.1.
    U00096 Genomic DNA. Translation: AAC76215.1.
    AP009048 Genomic DNA. Translation: BAE77227.1.
    PIRiA65109.
    RefSeqiNP_417650.1. NC_000913.3.
    WP_000673575.1. NZ_LN832404.1.

    3D structure databases

    Select the link destinations:
    PDBei
    RCSB PDBi
    PDBji
    Links Updated
    EntryMethodResolution (Å)ChainPositionsPDBsum
    4CSUelectron microscopy5.5091-390[»]
    ProteinModelPortaliP42641.
    SMRiP42641. Positions 4-336.
    ModBaseiSearch...
    MobiDBiSearch...

    Protein-protein interaction databases

    BioGridi4261647. 134 interactions.
    DIPiDIP-12273N.
    IntActiP42641. 28 interactions.
    MINTiMINT-1234247.
    STRINGi511145.b3183.

    Proteomic databases

    EPDiP42641.
    PaxDbiP42641.
    PRIDEiP42641.

    Protocols and materials databases

    Structural Biology KnowledgebaseSearch...

    Genome annotation databases

    EnsemblBacteriaiAAC76215; AAC76215; b3183.
    BAE77227; BAE77227; BAE77227.
    GeneIDi947694.
    KEGGiecj:JW3150.
    eco:b3183.
    PATRICi32121786. VBIEscCol129921_3277.

    Organism-specific databases

    EchoBASEiEB2647.
    EcoGeneiEG12795. obgE.

    Phylogenomic databases

    eggNOGiENOG4105C9R. Bacteria.
    COG0536. LUCA.
    HOGENOMiHOG000019084.
    InParanoidiP42641.
    KOiK03979.
    OMAiLVDFRYK.
    PhylomeDBiP42641.

    Enzyme and pathway databases

    BioCyciEcoCyc:G7656-MONOMER.
    ECOL316407:JW3150-MONOMER.

    Miscellaneous databases

    PROiP42641.

    Family and domain databases

    Gene3Di2.70.210.12. 1 hit.
    3.40.50.300. 1 hit.
    HAMAPiMF_01454. GTPase_Obg. 1 hit.
    InterProiIPR031167. G_OBG.
    IPR014100. GTP-bd_Obg/CgtA.
    IPR006074. GTP1-OBG_CS.
    IPR006169. GTP1_OBG_dom.
    IPR006073. GTP_binding_domain.
    IPR027417. P-loop_NTPase.
    [Graphical view]
    PANTHERiPTHR11702:SF3. PTHR11702:SF3. 1 hit.
    PfamiPF01018. GTP1_OBG. 1 hit.
    PF01926. MMR_HSR1. 1 hit.
    [Graphical view]
    PIRSFiPIRSF002401. GTP_bd_Obg/CgtA. 1 hit.
    PRINTSiPR00326. GTP1OBG.
    SUPFAMiSSF52540. SSF52540. 1 hit.
    SSF82051. SSF82051. 1 hit.
    TIGRFAMsiTIGR02729. Obg_CgtA. 1 hit.
    PROSITEiPS51710. G_OBG. 1 hit.
    PS00905. GTP1_OBG. 1 hit.
    [Graphical view]
    ProtoNetiSearch...

    Entry informationi

    Entry nameiOBG_ECOLI
    AccessioniPrimary (citable) accession number: P42641
    Secondary accession number(s): Q2M929
    Entry historyi
    Integrated into UniProtKB/Swiss-Prot: November 1, 1995
    Last sequence update: November 1, 1995
    Last modified: September 7, 2016
    This is version 129 of the entry and version 1 of the sequence. [Complete history]
    Entry statusiReviewed (UniProtKB/Swiss-Prot)
    Annotation programProkaryotic Protein Annotation Program

    Miscellaneousi

    Keywords - Technical termi

    3D-structure, Complete proteome, Reference proteome

    Documents

    1. Escherichia coli
      Escherichia coli (strain K12): entries and cross-references to EcoGene
    2. PDB cross-references
      Index of Protein Data Bank (PDB) cross-references
    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.