ID   CFI_PUEML               Reviewed;         224 AA.
AC   Q43056;
DT   15-JUL-1999, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   03-AUG-2022, entry version 84.
DE   RecName: Full=Chalcone--flavanone isomerase;
DE            Short=Chalcone isomerase;
DE            EC=5.5.1.6;
GN   Name=CHI;
OS   Pueraria montana var. lobata (Kudzu vine) (Pueraria lobata).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; fabids; Fabales; Fabaceae; Papilionoideae; 50 kb inversion clade;
OC   NPAAA clade; indigoferoid/millettioid clade; Phaseoleae; Pueraria.
OX   NCBI_TaxID=3893;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, AND MUTAGENESIS OF CYS-119.
RX   PubMed=8812858; DOI=10.1006/prep.1996.0091;
RA   Terai Y., Fujii I., Byun S.-H., Nakajima O., Hakamatsuka T., Ebizuka Y.,
RA   Sankawa U.;
RT   "Cloning of chalcone-flavanone isomerase cDNA from Pueraria lobata and its
RT   overexpression in Escherichia coli.";
RL   Protein Expr. Purif. 8:183-190(1996).
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:8812858}.
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; D63577; BAA09795.1; -; mRNA.
DR   AlphaFoldDB; Q43056; -.
DR   SMR; Q43056; -.
DR   BRENDA; 5.5.1.6; 5230.
DR   UniPathway; UPA00154; -.
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   1: Evidence at protein level;
KW   Flavonoid biosynthesis; Isomerase.
FT   CHAIN           1..224
FT                   /note="Chalcone--flavanone isomerase"
FT                   /id="PRO_0000166440"
FT   BINDING         53
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         118
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         195
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   SITE            111
FT                   /note="Important for catalytic activity"
FT                   /evidence="ECO:0000250"
FT   MUTAGEN         119
FT                   /note="C->A: No loss of activity."
FT                   /evidence="ECO:0000269|PubMed:8812858"
SQ   SEQUENCE   224 AA;  23804 MW;  6C45CC742D76AD1E CRC64;
     MAAAAAVATI SAVQVEFLEF PAVVTSPASG RTYFLGGAGE RGLTIEGKFI KFTGIGVYLE
     DKAVSSLAAK WKGKPSEELV ETLDFYRDII SGPFEKLIRG SKILPLSGVE YSKKVMENCV
     AHMKSVGTYG DAEAAAIEKF AEAFKNVNFQ PGATVFYRQS PDGVLGLSFS EDVTIPDNEA
     AVIENKAVSA AVLETMIGEH AVSPDLKRSL ASRLPAVLSH GIIV