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Protein

Ribosome-associated molecular chaperone SSB1

Gene

SSB1

Organism
Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

Ribosome-bound, Hsp70-type chaperone that assists in the cotranslational folding of newly synthesized proteins in the cytosol. Stimulates folding by interacting with nascent chains, binding to short, largely hydrophobic sequences exposed by unfolded proteins, thereby stabilizing longer, more slowly translated, and aggregation-prone nascent polypeptides and domains that cannot fold stably until fully synthesized. The Hsp70-protein substrate interaction depends on ATP-binding and on allosteric regulation between the NBD and the SBD. The ATP-bound state is characterized by a fast exchange rate of substrate (low affinity state), while in the ADP-bound state exchange is much slower (high affinity state). During the Hsp70 cycle, the chaperone switches between the ATP-bound state (open conformation) and the ADP-bound state (closed conformation) by major conformational rearrangements involving mainly the lid domain. Ssb cooperates with a specific Hsp40/Hsp70 co-chaperone termed the ribosome-associated complex (RAC), which stimulates the ATPase activity of the ribosome-associated pool of Ssbs and switches it to the high affinity substrate binding state. Hsp110 chaperone SSE1 and FES1 act as nucleotide exchange factors that cause substrate release.8 Publications

Miscellaneous

Present with 170000 molecules/cell in log phase SD medium.1 Publication

Catalytic activityi

ATP + H2O = ADP + phosphate.1 Publication

Kineticsi

kcat is 0.95 min(-1) with ATP as substrate (at 2.5 mM potassium acetate) and 0.81 min(-1) with ATP as substrate (at 100 mM potassium acetate).1 Publication
  1. KM=270 µM for ATP (at 2.5 mM potassium acetate)1 Publication
  2. KM=147 µM for ATP (at 100 mM potassium acetate)1 Publication

    Sites

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Binding sitei73ATPBy similarity1
    Binding sitei342ATP; via amide nitrogenBy similarity1

    Regions

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Nucleotide bindingi16 – 18ATPBy similarity3
    Nucleotide bindingi205 – 207ATPBy similarity3
    Nucleotide bindingi271 – 278ATPBy similarity8

    GO - Molecular functioni

    • ATPase activity Source: SGD
    • ATP binding Source: UniProtKB-KW
    • calmodulin binding Source: SGD
    • unfolded protein binding Source: SGD

    GO - Biological processi

    Keywordsi

    Molecular functionChaperone, Hydrolase
    Biological processProtein biosynthesis
    LigandATP-binding, Nucleotide-binding

    Enzyme and pathway databases

    BioCyciYEAST:G3O-29608-MONOMER
    ReactomeiR-SCE-3371453 Regulation of HSF1-mediated heat shock response

    Names & Taxonomyi

    Protein namesi
    Recommended name:
    Ribosome-associated molecular chaperone SSB11 Publication (EC:3.6.4.101 Publication)
    Alternative name(s):
    Cold-inducible protein YG1011 Publication
    Heat shock protein SSB11 Publication
    Hsp70 chaperone Ssb1 Publication
    Gene namesi
    Name:SSB11 Publication
    Synonyms:YG1011 Publication
    Ordered Locus Names:YDL229WImported
    OrganismiSaccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast)
    Taxonomic identifieri559292 [NCBI]
    Taxonomic lineageiEukaryotaFungiDikaryaAscomycotaSaccharomycotinaSaccharomycetesSaccharomycetalesSaccharomycetaceaeSaccharomyces
    Proteomesi
    • UP000002311 Componenti: Chromosome IV

    Organism-specific databases

    EuPathDBiFungiDB:YDL229W
    SGDiS000002388 SSB1

    Subcellular locationi

    Keywords - Cellular componenti

    Cytoplasm

    Pathology & Biotechi

    Mutagenesis

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Mutagenesisi73K → A: Unable to hydrolyze ATP and moderately reduces ribosome binding. 1 Publication1
    Mutagenesisi567 – 568KR → EE in SSB1-L(BC): Reduces ribosome-binding to less than 50%. 1 Publication2
    Mutagenesisi596 – 597RK → DD in SSB1-D1: Reduces ribosome-binding to less than 50%. 1 Publication2
    Mutagenesisi603 – 604KR → DD in SSB1-D2: Reduces ribosome-binding to less than 50%. 1 Publication2

    PTM / Processingi

    Molecule processing

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Initiator methionineiRemoved1 Publication
    ChainiPRO_00000783892 – 613Ribosome-associated molecular chaperone SSB1Add BLAST612

    Amino acid modifications

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Modified residuei2N-acetylalanine1 Publication1
    Modified residuei47PhosphothreonineCombined sources1
    Modified residuei431PhosphothreonineCombined sources1

    Keywords - PTMi

    Acetylation, Phosphoprotein

    Proteomic databases

    MaxQBiP11484
    PaxDbiP11484
    PRIDEiP11484
    TopDownProteomicsiP11484

    2D gel databases

    COMPLUYEAST-2DPAGEiP11484
    SWISS-2DPAGEiP11484
    UCD-2DPAGEiP11484

    PTM databases

    CarbonylDBiP11484
    iPTMnetiP11484

    Expressioni

    Inductioni

    Expression decreases after heat shock or during growth to stationary phase (PubMed:6761581, PubMed:2651414). Degraded during heat shock treatment (at protein level) (PubMed:7646503). Up-regulated upon carbon upshift and down-regulated upon amino acid limitation in an HSF1-dependent manner (PubMed:10322015).4 Publications

    Interactioni

    Subunit structurei

    Binds to ribosomes (PubMed:9670014, PubMed:1394434, PubMed:27917864). Binds close to the ribosomal tunnel exit via contacts with both ribosomal proteins RPL35, RPL39 and RPL19, and rRNA (PubMed:27882919). Directly interacts with nascent polypeptides. This interaction is dependent on the ribosome-associated complex (RAC) (PubMed:11929994, PubMed:23332755). Interacts with SSE1 (PubMed:16219770, PubMed:16221677, PubMed:23332755). Interacts with FES1 (PubMed:17132105). Interacts with NAP1 (PubMed:18086883).10 Publications

    Binary interactionsi

    GO - Molecular functioni

    Protein-protein interaction databases

    BioGridi31882, 795 interactors
    DIPiDIP-2254N
    IntActiP11484, 777 interactors
    MINTiP11484
    STRINGi4932.YDL229W

    Structurei

    Secondary structure

    1613
    Legend: HelixTurnBeta strandPDB Structure known for this area
    Show more details

    3D structure databases

    ProteinModelPortaliP11484
    SMRiP11484
    ModBaseiSearch...
    MobiDBiSearch...

    Miscellaneous databases

    EvolutionaryTraceiP11484

    Family & Domainsi

    Region

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Regioni2 – 391Nucleotide binding domain (NBD)By similarityAdd BLAST390
    Regioni392 – 402Inter-domain linkerBy similarityAdd BLAST11
    Regioni403 – 613Substrate binding domain (SBD)By similarityAdd BLAST211
    Regioni516 – 612Lid domain (SBDalpha)By similarityAdd BLAST97
    Regioni601 – 613Required for interaction with ribosomes1 PublicationAdd BLAST13

    Motif

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Motifi428 – 430Contributes to ribosome binding1 Publication3
    Motifi574 – 582Nuclear export signal1 Publication9

    Sequence similaritiesi

    Phylogenomic databases

    GeneTreeiENSGT00890000139503
    HOGENOMiHOG000228135
    InParanoidiP11484
    OMAiFEEINST
    OrthoDBiEOG092C1VPN

    Family and domain databases

    Gene3Di1.20.1270.10, 1 hit
    2.60.34.10, 1 hit
    InterProiView protein in InterPro
    IPR018181 Heat_shock_70_CS
    IPR029048 HSP70_C_sf
    IPR029047 HSP70_peptide-bd_sf
    IPR013126 Hsp_70_fam
    PANTHERiPTHR19375 PTHR19375, 1 hit
    PfamiView protein in Pfam
    PF00012 HSP70, 1 hit
    PRINTSiPR00301 HEATSHOCK70
    SUPFAMiSSF100920 SSF100920, 1 hit
    SSF100934 SSF100934, 1 hit
    PROSITEiView protein in PROSITE
    PS00297 HSP70_1, 1 hit
    PS00329 HSP70_2, 1 hit
    PS01036 HSP70_3, 1 hit

    Sequencei

    Sequence statusi: Complete.

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

    P11484-1 [UniParc]FASTAAdd to basket
    « Hide
            10         20         30         40         50
    MAEGVFQGAI GIDLGTTYSC VATYESSVEI IANEQGNRVT PSFVAFTPEE
    60 70 80 90 100
    RLIGDAAKNQ AALNPRNTVF DAKRLIGRRF DDESVQKDMK TWPFKVIDVD
    110 120 130 140 150
    GNPVIEVQYL EETKTFSPQE ISAMVLTKMK EIAEAKIGKK VEKAVITVPA
    160 170 180 190 200
    YFNDAQRQAT KDAGAISGLN VLRIINEPTA AAIAYGLGAG KSEKERHVLI
    210 220 230 240 250
    FDLGGGTFDV SLLHIAGGVY TVKSTSGNTH LGGQDFDTNL LEHFKAEFKK
    260 270 280 290 300
    KTGLDISDDA RALRRLRTAA ERAKRTLSSV TQTTVEVDSL FDGEDFESSL
    310 320 330 340 350
    TRARFEDLNA ALFKSTLEPV EQVLKDAKIS KSQIDEVVLV GGSTRIPKVQ
    360 370 380 390 400
    KLLSDFFDGK QLEKSINPDE AVAYGAAVQG AILTGQSTSD ETKDLLLLDV
    410 420 430 440 450
    APLSLGVGMQ GDMFGIVVPR NTTVPTIKRR TFTTCADNQT TVQFPVYQGE
    460 470 480 490 500
    RVNCKENTLL GEFDLKNIPM MPAGEPVLEA IFEVDANGIL KVTAVEKSTG
    510 520 530 540 550
    KSSNITISNA VGRLSSEEIE KMVNQAEEFK AADEAFAKKH EARQRLESYV
    560 570 580 590 600
    ASIEQTVTDP VLSSKLKRGS KSKIEAALSD ALAALQIEDP SADELRKAEV
    610
    GLKRVVTKAM SSR
    Length:613
    Mass (Da):66,602
    Last modified:January 23, 2007 - v3
    Checksum:iF16FA7C25A40321A
    GO

    Experimental Info

    Feature keyPosition(s)DescriptionActionsGraphical viewLength
    Sequence conflicti180 – 184AAAIA → VVVIV in AAA34692 (PubMed:6761581).Curated5
    Sequence conflicti189A → V in AAA34692 (PubMed:6761581).Curated1
    Sequence conflicti192S → F in AAA34692 (PubMed:6761581).Curated1

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    X13713 Genomic DNA Translation: CAA31995.1
    M25395 mRNA Translation: AAA35099.1
    Z74277 Genomic DNA Translation: CAA98807.1
    M17585 Genomic DNA Translation: AAA34692.1
    BK006938 Genomic DNA Translation: DAA11637.1
    PIRiS20149
    RefSeqiNP_010052.1, NM_001180289.1

    Genome annotation databases

    EnsemblFungiiYDL229W; YDL229W; YDL229W
    GeneIDi851369
    KEGGisce:YDL229W

    Similar proteinsi

    Cross-referencesi

    Sequence databases

    Select the link destinations:
    EMBLi
    GenBanki
    DDBJi
    Links Updated
    X13713 Genomic DNA Translation: CAA31995.1
    M25395 mRNA Translation: AAA35099.1
    Z74277 Genomic DNA Translation: CAA98807.1
    M17585 Genomic DNA Translation: AAA34692.1
    BK006938 Genomic DNA Translation: DAA11637.1
    PIRiS20149
    RefSeqiNP_010052.1, NM_001180289.1

    3D structure databases

    Select the link destinations:
    PDBei
    RCSB PDBi
    PDBji
    Links Updated
    PDB entryMethodResolution (Å)ChainPositionsPDBsum
    3GL1X-ray1.92A/B1-384[»]
    ProteinModelPortaliP11484
    SMRiP11484
    ModBaseiSearch...
    MobiDBiSearch...

    Protein-protein interaction databases

    BioGridi31882, 795 interactors
    DIPiDIP-2254N
    IntActiP11484, 777 interactors
    MINTiP11484
    STRINGi4932.YDL229W

    PTM databases

    CarbonylDBiP11484
    iPTMnetiP11484

    2D gel databases

    COMPLUYEAST-2DPAGEiP11484
    SWISS-2DPAGEiP11484
    UCD-2DPAGEiP11484

    Proteomic databases

    MaxQBiP11484
    PaxDbiP11484
    PRIDEiP11484
    TopDownProteomicsiP11484

    Protocols and materials databases

    Structural Biology KnowledgebaseSearch...

    Genome annotation databases

    EnsemblFungiiYDL229W; YDL229W; YDL229W
    GeneIDi851369
    KEGGisce:YDL229W

    Organism-specific databases

    EuPathDBiFungiDB:YDL229W
    SGDiS000002388 SSB1

    Phylogenomic databases

    GeneTreeiENSGT00890000139503
    HOGENOMiHOG000228135
    InParanoidiP11484
    OMAiFEEINST
    OrthoDBiEOG092C1VPN

    Enzyme and pathway databases

    BioCyciYEAST:G3O-29608-MONOMER
    ReactomeiR-SCE-3371453 Regulation of HSF1-mediated heat shock response

    Miscellaneous databases

    EvolutionaryTraceiP11484
    PROiPR:P11484

    Family and domain databases

    Gene3Di1.20.1270.10, 1 hit
    2.60.34.10, 1 hit
    InterProiView protein in InterPro
    IPR018181 Heat_shock_70_CS
    IPR029048 HSP70_C_sf
    IPR029047 HSP70_peptide-bd_sf
    IPR013126 Hsp_70_fam
    PANTHERiPTHR19375 PTHR19375, 1 hit
    PfamiView protein in Pfam
    PF00012 HSP70, 1 hit
    PRINTSiPR00301 HEATSHOCK70
    SUPFAMiSSF100920 SSF100920, 1 hit
    SSF100934 SSF100934, 1 hit
    PROSITEiView protein in PROSITE
    PS00297 HSP70_1, 1 hit
    PS00329 HSP70_2, 1 hit
    PS01036 HSP70_3, 1 hit
    ProtoNetiSearch...

    Entry informationi

    Entry nameiSSB1_YEAST
    AccessioniPrimary (citable) accession number: P11484
    Secondary accession number(s): D6VRC7, Q05834
    Entry historyiIntegrated into UniProtKB/Swiss-Prot: October 1, 1989
    Last sequence update: January 23, 2007
    Last modified: October 10, 2018
    This is version 188 of the entry and version 3 of the sequence. See complete history.
    Entry statusiReviewed (UniProtKB/Swiss-Prot)
    Annotation programFungal Protein Annotation Program

    Miscellaneousi

    Keywords - Technical termi

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

    Documents

    1. SIMILARITY comments
      Index of protein domains and families
    2. PDB cross-references
      Index of Protein Data Bank (PDB) cross-references
    3. Yeast
      Yeast (Saccharomyces cerevisiae): entries, gene names and cross-references to SGD
    4. Yeast chromosome IV
      Yeast (Saccharomyces cerevisiae) chromosome IV: entries and gene names
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