ID   SDIS_COMTE              Reviewed;         125 AA.
AC   P00947;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1991, sequence version 2.
DT   02-SEP-2026, entry version 129.
DE   RecName: Full=Steroid Delta-isomerase;
DE            EC=5.3.3.1;
DE   AltName: Full=Delta(5)-3-ketosteroid isomerase;
GN   Name=ksi;
OS   Comamonas testosteroni (Pseudomonas testosteroni).
OC   Bacteria; Pseudomonadati; Pseudomonadota; Betaproteobacteria;
OC   Burkholderiales; Comamonadaceae; Comamonas.
OX   NCBI_TaxID=285;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=3224818; DOI=10.1016/0378-1119(88)90384-8;
RA   Choi K.Y., Benisek W.F.;
RT   "Nucleotide sequence of the gene for the delta 5-3-ketosteroid isomerase of
RT   Pseudomonas testosteroni.";
RL   Gene 69:121-129(1988).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=3480517; DOI=10.1073/pnas.84.24.8893;
RA   Kuliopulos A., Shortle D., Talalay P.;
RT   "Isolation and sequencing of the gene encoding delta 5-3-ketosteroid
RT   isomerase of Pseudomonas testosteroni: overexpression of the protein.";
RL   Proc. Natl. Acad. Sci. U.S.A. 84:8893-8897(1987).
RN   [3]
RP   PRELIMINARY PROTEIN SEQUENCE.
RX   PubMed=5135313; DOI=10.1016/s0021-9258(19)45806-7;
RA   Benson A.M., Jarabak R., Talalay P.;
RT   "The amino acid sequence of delta 5-3-ketosteroid isomerase of Pseudomonas
RT   testosteroni.";
RL   J. Biol. Chem. 246:7514-7525(1971).
RN   [4]
RP   CHARACTERIZATION.
RX   PubMed=4753764; DOI=10.1016/0014-5793(73)80431-4;
RA   Weintraub H., Vincent F., Baulieu E.-E., Alfsen A.;
RT   "Molecular weight determination and structural studies of Pseudomonas
RT   testosteroni delta 5 leads to 4-3-oxosteroid isomerase (EC 5.3.3.1).";
RL   FEBS Lett. 37:82-88(1973).
RN   [5]
RP   X-RAY CRYSTALLOGRAPHY (2.3 ANGSTROMS).
RX   PubMed=9369474; DOI=10.1021/bi971546+;
RA   Kim S.-W., Cha S.-S., Cho H.-S., Kim J.-S., Ha N.-C., Cho M.-J., Joo S.,
RA   Kim K.-K., Choi K.-Y., Oh B.-H.;
RT   "High-resolution crystal structures of delta5-3-ketosteroid isomerase with
RT   and without a reaction intermediate analogue.";
RL   Biochemistry 36:14030-14036(1997).
RN   [6]
RP   STRUCTURE BY NMR, AND MUTAGENESIS OF ASP-99.
RX   PubMed=9103200; DOI=10.1126/science.276.5311.415;
RA   Wu Z.R., Ebrahimian S., Zawrotny M.E., Thornburg L.D., Perez-Alvarado G.C.,
RA   Brothers P., Pollack R.M., Summers M.F.;
RT   "Solution structure of 3-oxo-delta5-steroid isomerase.";
RL   Science 276:415-418(1997).
RN   [7]
RP   STRUCTURE BY NMR IN COMPLEX WITH PRODUCT ANALOG.
RX   PubMed=9778345; DOI=10.1021/bi981447b;
RA   Massiah M.A., Abeygunawardana C., Gittis A.G., Mildvan A.S.;
RT   "Solution structure of delta 5-3-ketosteroid isomerase complexed with the
RT   steroid 19-nortestosterone hemisuccinate.";
RL   Biochemistry 37:14701-14712(1998).
RN   [8]
RP   X-RAY CRYSTALLOGRAPHY (2.3 ANGSTROMS) IN COMPLEX WITH REACTION INTERMEDIATE
RP   ANALOG.
RX   PubMed=10551849; DOI=10.1074/jbc.274.46.32863;
RA   Cho H.-S., Ha N.-C., Choi G., Kim H.-J., Lee D., Oh K.S., Kim K.S., Lee W.,
RA   Choi K.Y., Oh B.-H.;
RT   "Crystal structure of delta(5)-3-ketosteroid isomerase from Pseudomonas
RT   testosteroni in complex with equilenin settles the correct hydrogen bonding
RT   scheme for transition state stabilization.";
RL   J. Biol. Chem. 274:32863-32868(1999).
RN   [9]
RP   X-RAY CRYSTALLOGRAPHY (2.3 ANGSTROMS) OF MUTANT ALA-39 IN COMPLEX WITH
RP   REACTION INTERMEDIATE ANALOG.
RX   PubMed=12852789; DOI=10.1042/bj20030263;
RA   Nam G.H., Cha S.-S., Yun Y.S., Oh Y.H., Hong B.H., Lee H.-S., Choi K.-Y.;
RT   "The conserved cis-Pro39 residue plays a crucial role in the proper
RT   positioning of the catalytic base Asp38 in ketosteroid isomerase from
RT   Comamonas testosteroni.";
RL   Biochem. J. 375:297-305(2003).
RN   [10]
RP   X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS) OF MUTANT TRP-116.
RX   PubMed=12734184; DOI=10.1074/jbc.m302166200;
RA   Yun Y.S., Lee T.-H., Nam G.H., Jang do S., Shin S., Oh B.-H., Choi K.-Y.;
RT   "Origin of the different pH activity profile in two homologous ketosteroid
RT   isomerases.";
RL   J. Biol. Chem. 278:28229-28236(2003).
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a 3-oxo-Delta(5)-steroid = a 3-oxo-Delta(4)-steroid;
CC         Xref=Rhea:RHEA:14709, ChEBI:CHEBI:47907, ChEBI:CHEBI:47909;
CC         EC=5.3.3.1;
CC   -!- SUBUNIT: Homodimer. {ECO:0000269|PubMed:10551849,
CC       ECO:0000269|PubMed:12852789, ECO:0000269|PubMed:9778345}.
CC   -!- INDUCTION: By steroids.
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DR   EMBL; M22749; AAA25872.1; -; Genomic_DNA.
DR   EMBL; J03568; AAA25871.1; -; Genomic_DNA.
DR   PIR; JT0336; SIPSDT.
DR   RefSeq; WP_003078309.1; NZ_BBJZ01000017.1.
DR   PDB; 1BUQ; NMR; -; A/B=1-125.
DR   PDB; 1ISK; NMR; -; A/B=1-125.
DR   PDB; 1OCV; X-ray; 2.00 A; A/B/C/D=1-125.
DR   PDB; 1OGZ; X-ray; 2.30 A; A=1-125.
DR   PDB; 1OHP; X-ray; 1.53 A; A/B/C/D=1-125.
DR   PDB; 1OHS; X-ray; 1.70 A; A/B/C/D=1-125.
DR   PDB; 1QJG; X-ray; 2.30 A; A/B/C/D/E/F=1-125.
DR   PDB; 3M8C; X-ray; 2.10 A; A/B/C/D=1-125.
DR   PDB; 3MHE; X-ray; 1.72 A; A/B=1-125.
DR   PDB; 3MKI; X-ray; 2.00 A; A/B/C/D=1-125.
DR   PDB; 3MYT; X-ray; 1.96 A; A/B/C/D=1-125.
DR   PDB; 3NBR; X-ray; 1.73 A; A=1-125.
DR   PDB; 3NHX; X-ray; 1.59 A; A=1-125.
DR   PDB; 3NM2; X-ray; 1.89 A; A=1-125.
DR   PDB; 3NUV; X-ray; 1.76 A; A/B=1-125.
DR   PDB; 3NXJ; X-ray; 1.97 A; A/B=1-125.
DR   PDB; 3OV4; X-ray; 1.83 A; A/B/C/D=1-125.
DR   PDB; 3T8U; X-ray; 2.50 A; A/B/C/D=1-125.
DR   PDB; 3UNL; X-ray; 2.52 A; A/B/C/D=1-125.
DR   PDB; 4L7K; X-ray; 2.10 A; A/B/C/D/E/F/G/H/I/J/K/O=1-125.
DR   PDB; 5DRE; X-ray; 2.15 A; A=1-125.
DR   PDB; 5UGI; X-ray; 1.80 A; A=1-125.
DR   PDB; 6UAD; X-ray; 1.75 A; A=1-125.
DR   PDB; 6UAE; X-ray; 1.93 A; A/B/C/D=1-125.
DR   PDB; 8CHO; X-ray; 2.30 A; A=1-125.
DR   AlphaFoldDB; P00947; -.
DR   BMRB; P00947; -.
DR   MDRepo; P00947; -.
DR   SMR; P00947; -.
DR   DrugBank; DB01561; Androstanedione.
DR   DrugBank; DB03515; Equilenin.
DR   DrugBank; DB04693; Estrane-3,17-dione.
DR   DrugBank; DB08308; SUCCINIC ACID MONO-(13-METHYL-3-OXO-2,3,6,7,8,9,10,11,12,13,14,15,16,17-TETRADECAHYDRO-1H-CYCLOPENTA[A]PHENANTHREN-17-YL) ESTER.
DR   GeneID; 64000200; -.
DR   KEGG; ag:AAA25872; -.
DR   BRENDA; 5.3.3.1; 1590.
DR   SABIO-RK; P00947; -.
DR   EvolutionaryTrace; P00947; -.
DR   GO; GO:0004769; F:steroid Delta-isomerase activity; IEA:UniProtKB-EC.
DR   CDD; cd00781; ketosteroid_isomerase; 1.
DR   Gene3D; 3.10.450.50; -; 1.
DR   InterPro; IPR039256; Ketosteroid_isomerase.
DR   InterPro; IPR032710; NTF2-like_dom_sf.
DR   InterPro; IPR037401; SnoaL-like.
DR   InterPro; IPR011944; Steroid_delta5-4_isomerase.
DR   NCBIfam; TIGR02246; SgcJ/EcaC family oxidoreductase; 1.
DR   Pfam; PF12680; SnoaL_2; 1.
DR   SUPFAM; SSF54427; NTF2-like; 1.
DR   PDBsum; 1BUQ; -.
DR   PDBsum; 1ISK; -.
DR   PDBsum; 1OCV; -.
DR   PDBsum; 1OGZ; -.
DR   PDBsum; 1OHP; -.
DR   PDBsum; 1OHS; -.
DR   PDBsum; 1QJG; -.
DR   PDBsum; 3M8C; -.
DR   PDBsum; 3MHE; -.
DR   PDBsum; 3MKI; -.
DR   PDBsum; 3MYT; -.
DR   PDBsum; 3NBR; -.
DR   PDBsum; 3NHX; -.
DR   PDBsum; 3NM2; -.
DR   PDBsum; 3NUV; -.
DR   PDBsum; 3NXJ; -.
DR   PDBsum; 3OV4; -.
DR   PDBsum; 3T8U; -.
DR   PDBsum; 3UNL; -.
DR   PDBsum; 4L7K; -.
DR   PDBsum; 5DRE; -.
DR   PDBsum; 5UGI; -.
DR   PDBsum; 6UAD; -.
DR   PDBsum; 6UAE; -.
DR   PDBsum; 8CHO; -.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; Isomerase; Lipid metabolism;
KW   Steroid metabolism.
FT   CHAIN           1..125
FT                   /note="Steroid Delta-isomerase"
FT                   /id="PRO_0000097644"
FT   ACT_SITE        14
FT                   /note="Proton donor"
FT   ACT_SITE        38
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000269|PubMed:3480517"
FT   BINDING         99
FT                   /ligand="substrate"
FT   MUTAGEN         39
FT                   /note="P->A: Perturbs active site geometry and lowers
FT                   activity."
FT   MUTAGEN         99
FT                   /note="D->A: Lowers activity 3000-fold."
FT                   /evidence="ECO:0000269|PubMed:9103200"
FT   MUTAGEN         116
FT                   /note="F->W: Slightly lower activity at neutral pH.
FT                   Increased catalytic activity at pH 3.8."
FT   HELIX           4..20
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   HELIX           23..27
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   STRAND          30..39
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   STRAND          45..47
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   HELIX           48..58
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   STRAND          64..67
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   STRAND          72..74
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   STRAND          77..88
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   STRAND          91..95
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   STRAND          98..103
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   TURN            105..107
FT                   /evidence="ECO:0007829|PDB:1ISK"
FT   STRAND          109..115
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   HELIX           118..120
FT                   /evidence="ECO:0007829|PDB:1OHP"
FT   STRAND          121..123
FT                   /evidence="ECO:0007829|PDB:1OHP"
SQ   SEQUENCE   125 AA;  13398 MW;  2ECD410D4B929430 CRC64;
     MNTPEHMTAV VQRYVAALNA GDLDGIVALF ADDATVEDPV GSEPRSGTAA IREFYANSLK
     LPLAVELTQE VRAVANEAAF AFTVSFEYQG RKTVVAPIDH FRFNGAGKVV SMRALFGEKN
     IHAGA
//