ID   CFI_TOBAC               Reviewed;         244 AA.
AC   Q33DL3;
DT   11-SEP-2007, integrated into UniProtKB/Swiss-Prot.
DT   06-DEC-2005, sequence version 1.
DT   03-AUG-2022, entry version 60.
DE   RecName: Full=Chalcone--flavanone isomerase;
DE            Short=Chalcone isomerase;
DE            EC=5.5.1.6;
GN   Name=CHI; Synonyms=CHI-1;
OS   Nicotiana tabacum (Common tobacco).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   asterids; lamiids; Solanales; Solanaceae; Nicotianoideae; Nicotianeae;
OC   Nicotiana.
OX   NCBI_TaxID=4097;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], AND FUNCTION.
RC   STRAIN=cv. SR1; TISSUE=Petal;
RX   PubMed=16226261; DOI=10.1016/j.febslet.2005.09.073;
RA   Nishihara M., Nakatsuka T., Yamamura S.;
RT   "Flavonoid components and flower color change in transgenic tobacco plants
RT   by suppression of chalcone isomerase gene.";
RL   FEBS Lett. 579:6074-6078(2005).
CC   -!- FUNCTION: Catalyzes the intramolecular cyclization of bicyclic
CC       chalcones into tricyclic (S)-flavanones. Responsible for the
CC       isomerization of 4,2',4',6'-tetrahydroxychalcone (also termed chalcone)
CC       into naringenin. {ECO:0000269|PubMed:16226261}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a chalcone = a flavanone.; EC=5.5.1.6;
CC   -!- PATHWAY: Secondary metabolite biosynthesis; flavonoid biosynthesis.
CC   -!- MISCELLANEOUS: Part of the biosynthetic pathway for all classes of
CC       flavonoids, a large class of secondary plant metabolites, many of which
CC       are brightly colored.
CC   -!- SIMILARITY: Belongs to the chalcone isomerase family. {ECO:0000305}.
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DR   EMBL; AB213651; BAE48085.1; -; mRNA.
DR   RefSeq; NP_001312216.1; NM_001325287.1.
DR   AlphaFoldDB; Q33DL3; -.
DR   SMR; Q33DL3; -.
DR   STRING; 4097.Q33DL3; -.
DR   PRIDE; Q33DL3; -.
DR   GeneID; 107779699; -.
DR   KEGG; nta:107779699; -.
DR   OMA; FVEIWKS; -.
DR   PhylomeDB; Q33DL3; -.
DR   BRENDA; 5.5.1.6; 3645.
DR   UniPathway; UPA00154; -.
DR   Proteomes; UP000084051; Unplaced.
DR   GO; GO:0045430; F:chalcone isomerase activity; IEA:UniProtKB-EC.
DR   GO; GO:0009813; P:flavonoid biosynthetic process; IEA:UniProtKB-UniPathway.
DR   Gene3D; 1.10.890.20; -; 1.
DR   Gene3D; 3.50.70.10; -; 1.
DR   InterPro; IPR044164; CFI.
DR   InterPro; IPR016087; Chalcone_isomerase.
DR   InterPro; IPR016088; Chalcone_isomerase_3-sand.
DR   InterPro; IPR016089; Chalcone_isomerase_bundle_sf.
DR   InterPro; IPR036298; Chalcone_isomerase_sf.
DR   PANTHER; PTHR28039; PTHR28039; 1.
DR   Pfam; PF02431; Chalcone; 1.
DR   SUPFAM; SSF54626; SSF54626; 1.
PE   2: Evidence at transcript level;
KW   Flavonoid biosynthesis; Isomerase; Reference proteome.
FT   CHAIN           1..244
FT                   /note="Chalcone--flavanone isomerase"
FT                   /id="PRO_0000300854"
FT   BINDING         45
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         110
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         187
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   SITE            103
FT                   /note="Important for catalytic activity"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   244 AA;  26426 MW;  273965030FE769E7 CRC64;
     MESITIENYV FPSTMVNPPG STNTFFLAGA GNRGLEIEGK FVKFTAIGVY LEESALPFLA
     AKWKSKSSEE LANSLDFFRD IVTGPFEKFT RVTMILPLTG KQYSEKVAEN CVAHWKAIGT
     YTDAESQAIE KLLNIFQNET FPPGASILFT QSPVGALTIS FIKDDSITGT GNAVIENKQL
     SEAVLESIIG KHGVSPAAKC SIAERVSGLF KKSYADASVF EKPGIEKSSD PVIEEKPTIP
     EIGV