ID   IBPB_ECOSM              Reviewed;         142 AA.
AC   B1LL11;
DT   28-JUL-2009, integrated into UniProtKB/Swiss-Prot.
DT   29-APR-2008, sequence version 1.
DT   25-MAY-2022, entry version 73.
DE   RecName: Full=Small heat shock protein IbpB {ECO:0000255|HAMAP-Rule:MF_02001};
DE   AltName: Full=16 kDa heat shock protein B {ECO:0000255|HAMAP-Rule:MF_02001};
GN   Name=ibpB {ECO:0000255|HAMAP-Rule:MF_02001};
GN   OrderedLocusNames=EcSMS35_4051;
OS   Escherichia coli (strain SMS-3-5 / SECEC).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Escherichia.
OX   NCBI_TaxID=439855;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=SMS-3-5 / SECEC;
RX   PubMed=18708504; DOI=10.1128/jb.00661-08;
RA   Fricke W.F., Wright M.S., Lindell A.H., Harkins D.M., Baker-Austin C.,
RA   Ravel J., Stepanauskas R.;
RT   "Insights into the environmental resistance gene pool from the genome
RT   sequence of the multidrug-resistant environmental isolate Escherichia coli
RT   SMS-3-5.";
RL   J. Bacteriol. 190:6779-6794(2008).
CC   -!- FUNCTION: Associates with aggregated proteins, together with IbpA, to
CC       stabilize and protect them from irreversible denaturation and extensive
CC       proteolysis during heat shock and oxidative stress. Aggregated proteins
CC       bound to the IbpAB complex are more efficiently refolded and
CC       reactivated by the ATP-dependent chaperone systems ClpB and
CC       DnaK/DnaJ/GrpE. Its activity is ATP-independent. {ECO:0000255|HAMAP-
CC       Rule:MF_02001}.
CC   -!- SUBUNIT: Homodimer. Forms homomultimers of about 100-150 subunits at
CC       optimal growth temperatures. Conformation changes to oligomers at high
CC       temperatures or high ionic concentrations. The decrease in size of the
CC       multimers is accompanied by an increase in chaperone activity.
CC       {ECO:0000255|HAMAP-Rule:MF_02001}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000255|HAMAP-Rule:MF_02001}.
CC   -!- DOMAIN: The N- and C-terminal flexible termini are involved in
CC       oligomerization and in the binding of non-native substrate proteins,
CC       and are essential for chaperone activity. {ECO:0000255|HAMAP-
CC       Rule:MF_02001}.
CC   -!- SIMILARITY: Belongs to the small heat shock protein (HSP20) family.
CC       {ECO:0000255|HAMAP-Rule:MF_02001, ECO:0000255|PROSITE-
CC       ProRule:PRU00285}.
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DR   EMBL; CP000970; ACB16859.1; -; Genomic_DNA.
DR   RefSeq; WP_001243431.1; NC_010498.1.
DR   AlphaFoldDB; B1LL11; -.
DR   SMR; B1LL11; -.
DR   EnsemblBacteria; ACB16859; ACB16859; EcSMS35_4051.
DR   GeneID; 67417681; -.
DR   KEGG; ecm:EcSMS35_4051; -.
DR   HOGENOM; CLU_046737_4_2_6; -.
DR   OMA; SGNEGYP; -.
DR   Proteomes; UP000007011; Chromosome.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0050821; P:protein stabilization; IEA:UniProtKB-UniRule.
DR   CDD; cd06470; ACD_IbpA-B_like; 1.
DR   Gene3D; 2.60.40.790; -; 1.
DR   HAMAP; MF_02001; HSP20_IbpB; 1.
DR   InterPro; IPR002068; A-crystallin/Hsp20_dom.
DR   InterPro; IPR037913; ACD_IbpA/B.
DR   InterPro; IPR008978; HSP20-like_chaperone.
DR   InterPro; IPR022848; HSP20_IbpB.
DR   Pfam; PF00011; HSP20; 1.
DR   SUPFAM; SSF49764; SSF49764; 1.
DR   PROSITE; PS01031; SHSP; 1.
PE   3: Inferred from homology;
KW   Chaperone; Cytoplasm; Stress response.
FT   CHAIN           1..142
FT                   /note="Small heat shock protein IbpB"
FT                   /id="PRO_1000189105"
FT   DOMAIN          26..137
FT                   /note="sHSP"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00285"
SQ   SEQUENCE   142 AA;  16093 MW;  7666BB1BDB8A673A CRC64;
     MRNFDLSPLM RQWIGFDKLA NALQNAGESQ SFPPYNIEKS DDNHYRITLA LAGFRQEDLE
     IQLEGTRLSV KGTPEQPKEE KKWLHQGLMN QPFSLSFTLA ENMEVSGATF VNGLLHIDLI
     RNEPEPIAAQ RIAISERPAL NS