ID   MI40B_XENLA             Reviewed;         139 AA.
AC   Q63ZK1;
DT   16-MAY-2006, integrated into UniProtKB/Swiss-Prot.
DT   25-OCT-2004, sequence version 1.
DT   03-AUG-2022, entry version 56.
DE   RecName: Full=Mitochondrial intermembrane space import and assembly protein 40-B;
DE   AltName: Full=Coiled-coil-helix-coiled-coil-helix domain-containing protein 4-B;
GN   Name=chchd4-b; Synonyms=mia40-b;
OS   Xenopus laevis (African clawed frog).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Amphibia;
OC   Batrachia; Anura; Pipoidea; Pipidae; Xenopodinae; Xenopus; Xenopus.
OX   NCBI_TaxID=8355;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RG   NIH - Xenopus Gene Collection (XGC) project;
RL   Submitted (SEP-2004) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Central component of a redox-sensitive mitochondrial
CC       intermembrane space import machinery which is required for the
CC       biogenesis of respiratory chain complexes (By similarity). Functions as
CC       chaperone and catalyzes the formation of disulfide bonds in substrate
CC       proteins, such as COX17 or MICU1. Required for the import and folding
CC       of small cysteine-containing proteins (small Tim) in the mitochondrial
CC       intermembrane space (IMS). Precursor proteins to be imported into the
CC       IMS are translocated in their reduced form into the mitochondria.
CC       {ECO:0000250|UniProtKB:Q2KHZ4, ECO:0000250|UniProtKB:Q8N4Q1}.
CC   -!- SUBUNIT: Monomer. Can form homooligomers.
CC       {ECO:0000250|UniProtKB:Q8N4Q1}.
CC   -!- SUBCELLULAR LOCATION: Mitochondrion intermembrane space
CC       {ECO:0000250|UniProtKB:Q8N4Q1}.
CC   -!- DOMAIN: The CHCH domain contains a conserved twin Cys-X(9)-Cys motif
CC       which is required for import and stability of MIA40 in mitochondria.
CC       {ECO:0000250}.
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DR   EMBL; BC082911; AAH82911.1; -; mRNA.
DR   RefSeq; NP_001088092.1; NM_001094623.1.
DR   AlphaFoldDB; Q63ZK1; -.
DR   SMR; Q63ZK1; -.
DR   DNASU; 494790; -.
DR   GeneID; 494790; -.
DR   KEGG; xla:494790; -.
DR   CTD; 494790; -.
DR   Xenbase; XB-GENE-6255306; chchd4.S.
DR   Proteomes; UP000186698; Chromosome 4S.
DR   Bgee; 494790; Expressed in neurula embryo and 19 other tissues.
DR   GO; GO:0005758; C:mitochondrial intermembrane space; ISS:UniProtKB.
DR   GO; GO:0015035; F:protein-disulfide reductase activity; ISS:UniProtKB.
DR   GO; GO:0051084; P:'de novo' post-translational protein folding; ISS:UniProtKB.
DR   GO; GO:0045041; P:protein import into mitochondrial intermembrane space; ISS:UniProtKB.
DR   GO; GO:0022417; P:protein maturation by protein folding; ISS:UniProtKB.
DR   InterPro; IPR010625; CHCH.
DR   InterPro; IPR039289; CHCHD4.
DR   PANTHER; PTHR21622; PTHR21622; 1.
DR   Pfam; PF06747; CHCH; 1.
DR   PROSITE; PS51808; CHCH; 1.
PE   2: Evidence at transcript level;
KW   Disulfide bond; Mitochondrion; Oxidoreductase; Protein transport;
KW   Redox-active center; Reference proteome; Translocation; Transport.
FT   CHAIN           1..139
FT                   /note="Mitochondrial intermembrane space import and
FT                   assembly protein 40-B"
FT                   /id="PRO_0000235280"
FT   DOMAIN          61..105
FT                   /note="CHCH"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01150"
FT   REGION          102..139
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   MOTIF           64..74
FT                   /note="Cx9C motif 1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01150"
FT   MOTIF           87..97
FT                   /note="Cx9C motif 2"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01150"
FT   COMPBIAS        118..139
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   DISULFID        53..55
FT                   /note="Redox-active"
FT                   /evidence="ECO:0000250|UniProtKB:Q8N4Q1"
FT   DISULFID        64..97
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01150"
FT   DISULFID        74..87
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01150"
SQ   SEQUENCE   139 AA;  15754 MW;  E95A57EE3253F45D CRC64;
     MSYCRQEGKD KIIFVTKEDH ETPSSAELIA DDPNDPFEEQ GLILPNGDIN WNCPCLGGMA
     SGPCGEQFKS AFSCFHYSQE EIKGSDCLDQ FRAMQECMQK YPELYPQEDD EDELEKEKQN
     KDEESSVTQS SDTKEESSS