ID   CFI1_PETHY              Reviewed;         241 AA.
AC   P11650;
DT   01-OCT-1989, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1989, sequence version 1.
DT   03-AUG-2022, entry version 93.
DE   RecName: Full=Chalcone--flavanone isomerase A;
DE            Short=CHI-A;
DE            Short=Chalcone isomerase A;
DE            EC=5.5.1.6;
GN   Name=CHI1; Synonyms=CHIA, PO;
OS   Petunia hybrida (Petunia).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   asterids; lamiids; Solanales; Solanaceae; Petunioideae; Petunia.
OX   NCBI_TaxID=4102;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=cv. Violet 30; TISSUE=Leaf;
RA   van Tunen A.J., Hartman S.A., Mur L.A., Mol J.N.M.;
RT   "Regulation of chalone flavanone isomerase (CHI) gene expression in Petunia
RT   hybrida: the use of alternative promoters in corolla anthers and pollen.";
RL   Plant Mol. Biol. 12:539-551(1989).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [MRNA], TISSUE SPECIFICITY, DEVELOPMENTAL STAGE, AND
RP   INDUCTION BY UV LIGHT.
RC   STRAIN=cv. R27; TISSUE=Corolla;
RX   PubMed=3409864;
RA   van Tunen A.J., Koes R.E., Spelt C.E., van der Krol A.R., Stuitje A.R.,
RA   Mol J.N.M.;
RT   "Cloning of the two chalcone flavanone isomerase genes from Petunia
RT   hybrida: coordinate, light-regulated and differential expression of
RT   flavonoid genes.";
RL   EMBO J. 7:1257-1263(1988).
RN   [3]
RP   FUNCTION.
RC   STRAIN=cv. Violet 30; TISSUE=Anther tapetum;
RX   PubMed=1824333; DOI=10.1105/tpc.3.1.39;
RA   van Tunen A.J., Mur L.A., Recourt K., Gerats A.G.M., Mol J.N.M.;
RT   "Regulation and manipulation of flavonoid gene expression in anthers of
RT   petunia: the molecular basis of the Po mutation.";
RL   Plant Cell 3:39-48(1991).
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:1824333}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a chalcone = a flavanone.; EC=5.5.1.6;
CC   -!- PATHWAY: Secondary metabolite biosynthesis; flavonoid biosynthesis.
CC   -!- TISSUE SPECIFICITY: Flowers. {ECO:0000269|PubMed:3409864}.
CC   -!- DEVELOPMENTAL STAGE: Early stages of flower development.
CC       {ECO:0000269|PubMed:3409864}.
CC   -!- INDUCTION: By UV light. {ECO:0000269|PubMed:3409864}.
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}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   EMBL; X14589; CAA32729.1; -; Genomic_DNA.
DR   EMBL; Y00852; CAA68769.1; -; mRNA.
DR   PIR; JQ0962; ISPJA1.
DR   PIR; S04725; ISPJCA.
DR   AlphaFoldDB; P11650; -.
DR   SMR; P11650; -.
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   2: Evidence at transcript level;
KW   Flavonoid biosynthesis; Isomerase.
FT   CHAIN           1..241
FT                   /note="Chalcone--flavanone isomerase A"
FT                   /id="PRO_0000166437"
FT   BINDING         50
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         115
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         192
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   SITE            108
FT                   /note="Important for catalytic activity"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   241 AA;  26089 MW;  5F459A524A874325 CRC64;
     MSPPVSVTKM QVENYAFAPT VNPAGSTNTL FLAGAGHRGL EIEGKFVKFT AIGVYLEESA
     IPFLAEKWKG KTPQELTDSV EFFRDVVTGP FEKFTRVTMI LPLTGKQYSE KVAENCVAHW
     KGIGTYTDDE GRAIEKFLDV FRSETFPPGA SIMFTQSPLG LLTISFAKDD SVTGTANAVI
     ENKQLSEAVL ESIIGKHGVS PAAKCSVAER VAELLKKSYA EEASVFGKPE TEKSTIPVIG
     V