CFI1_MEDSA
ID CFI1_MEDSA Reviewed; 222 AA.
AC P28012;
DT 01-AUG-1992, integrated into UniProtKB/Swiss-Prot.
DT 01-AUG-1992, sequence version 1.
DT 03-AUG-2022, entry version 104.
DE RecName: Full=Chalcone--flavanone isomerase 1;
DE Short=Chalcone isomerase 1;
DE EC=5.5.1.6;
GN Name=CHI1; Synonyms=CHI-1;
OS Medicago sativa (Alfalfa).
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; Hologalegina; IRL clade; Trifolieae; Medicago.
OX NCBI_TaxID=3879;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA].
RC STRAIN=cv. Iroquois;
RX PubMed=8193301; DOI=10.1007/bf00029858;
RA McKhann H.I., Hirsch A.M.;
RT "Isolation of chalcone synthase and chalcone isomerase cDNAs from alfalfa
RT (Medicago sativa L.): highest transcript levels occur in young roots and
RT root tips.";
RL Plant Mol. Biol. 24:767-777(1994).
RN [2]
RP ERRATUM OF PUBMED:8193301.
RA McKhann H.I., Hirsch A.M.;
RL Plant Mol. Biol. 25:759-759(1994).
RN [3]
RP X-RAY CRYSTALLOGRAPHY (1.85 ANGSTROMS) IN COMPLEX WITH (2S)-NARINGENIN,
RP FUNCTION, BIOPHYSICOCHEMICAL PROPERTIES, AND MUTAGENESIS OF TYR-106.
RX PubMed=10966651; DOI=10.1038/79025;
RA Jez J.M., Bowman M.E., Dixon R.A., Noel J.P.;
RT "Structure and mechanism of the evolutionarily unique plant enzyme chalcone
RT isomerase.";
RL Nat. Struct. Biol. 7:786-791(2000).
RN [4]
RP X-RAY CRYSTALLOGRAPHY (2.3 ANGSTROMS), FUNCTION, BIOPHYSICOCHEMICAL
RP PROPERTIES, AND MUTAGENESIS OF THR-48; TYR-106; ASN-113 AND THR-190.
RX PubMed=11955065; DOI=10.1021/bi0255266;
RA Jez J.M., Bowman M.E., Noel J.P.;
RT "Role of hydrogen bonds in the reaction mechanism of chalcone isomerase.";
RL Biochemistry 41:5168-5176(2002).
RN [5]
RP X-RAY CRYSTALLOGRAPHY (2.1 ANGSTROMS), FUNCTION, AND BIOPHYSICOCHEMICAL
RP PROPERTIES.
RX PubMed=11698411; DOI=10.1074/jbc.m109224200;
RA Jez J.M., Noel J.P.;
RT "Reaction mechanism of chalcone isomerase. pH dependence, diffusion
RT control, and product binding differences.";
RL J. Biol. Chem. 277:1361-1369(2002).
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:10966651,
CC ECO:0000269|PubMed:11698411, ECO:0000269|PubMed:11955065}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a chalcone = a flavanone.; EC=5.5.1.6;
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=8.4 uM for 4,2',4'-trihydroxychalcone (at pH 7.5 and 25 degrees
CC Celsius) {ECO:0000269|PubMed:10966651, ECO:0000269|PubMed:11698411,
CC ECO:0000269|PubMed:11955065};
CC KM=15.7 uM for 6'-deoxychalcone (at pH 7.5 and 25 degrees Celsius)
CC {ECO:0000269|PubMed:10966651, ECO:0000269|PubMed:11698411,
CC ECO:0000269|PubMed:11955065};
CC KM=22.7 uM for 2',4'-dihydroxychalcone (at pH 7.5 and 25 degrees
CC Celsius) {ECO:0000269|PubMed:10966651, ECO:0000269|PubMed:11698411,
CC ECO:0000269|PubMed:11955065};
CC KM=42.5 uM for 4,2'-dihydroxychalcone (at pH 7.5 and 25 degrees
CC Celsius) {ECO:0000269|PubMed:10966651, ECO:0000269|PubMed:11698411,
CC ECO:0000269|PubMed:11955065};
CC KM=112 uM for 4,2',4',6'-tetrahydroxychalcone (at pH 7.5 and 25
CC degrees Celsius) {ECO:0000269|PubMed:10966651,
CC ECO:0000269|PubMed:11698411, ECO:0000269|PubMed:11955065};
CC pH dependence:
CC Optimum pH is 7-8.5 with 4,2',4'-trihydroxychalcone as substrate, at
CC 25 degrees Celsius. {ECO:0000269|PubMed:10966651,
CC ECO:0000269|PubMed:11698411, ECO:0000269|PubMed:11955065};
CC -!- PATHWAY: Secondary metabolite biosynthesis; flavonoid biosynthesis.
CC -!- DEVELOPMENTAL STAGE: Highest expression in young root tips.
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; M91079; AAB41524.1; -; mRNA.
DR PIR; S44371; S44371.
DR PDB; 1EYP; X-ray; 2.50 A; A/B=1-222.
DR PDB; 1EYQ; X-ray; 1.85 A; A/B=1-222.
DR PDB; 1FM7; X-ray; 2.30 A; A/B=1-222.
DR PDB; 1FM8; X-ray; 2.30 A; A/B=1-222.
DR PDB; 1JEP; X-ray; 2.10 A; A/B=1-222.
DR PDB; 1JX0; X-ray; 2.85 A; A/B=1-222.
DR PDB; 1JX1; X-ray; 2.30 A; A/B/C/D/E/F=1-222.
DR PDB; 6CJN; X-ray; 2.40 A; A/B=1-222.
DR PDB; 6CJO; X-ray; 2.40 A; A/B=1-222.
DR PDBsum; 1EYP; -.
DR PDBsum; 1EYQ; -.
DR PDBsum; 1FM7; -.
DR PDBsum; 1FM8; -.
DR PDBsum; 1JEP; -.
DR PDBsum; 1JX0; -.
DR PDBsum; 1JX1; -.
DR PDBsum; 6CJN; -.
DR PDBsum; 6CJO; -.
DR AlphaFoldDB; P28012; -.
DR SMR; P28012; -.
DR BioCyc; MetaCyc:MON-18291; -.
DR BRENDA; 5.5.1.6; 3078.
DR SABIO-RK; P28012; -.
DR UniPathway; UPA00154; -.
DR EvolutionaryTrace; P28012; -.
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 3D-structure; Flavonoid biosynthesis; Isomerase.
FT CHAIN 1..222
FT /note="Chalcone--flavanone isomerase 1"
FT /id="PRO_0000166434"
FT BINDING 48
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 113
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 190
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT SITE 106
FT /note="Important for catalytic activity"
FT MUTAGEN 48
FT /note="T->A: Strongly reduced reaction rate."
FT /evidence="ECO:0000269|PubMed:11955065"
FT MUTAGEN 48
FT /note="T->S: Reduced reaction rate."
FT /evidence="ECO:0000269|PubMed:11955065"
FT MUTAGEN 106
FT /note="Y->F: Strongly reduced reaction rate."
FT /evidence="ECO:0000269|PubMed:10966651,
FT ECO:0000269|PubMed:11955065"
FT MUTAGEN 113
FT /note="N->A: Reduced reaction rate."
FT /evidence="ECO:0000269|PubMed:11955065"
FT MUTAGEN 190
FT /note="T->A: Reduced reaction rate."
FT /evidence="ECO:0000269|PubMed:11955065"
FT STRAND 8..10
FT /evidence="ECO:0007829|PDB:1EYQ"
FT STRAND 13..15
FT /evidence="ECO:0007829|PDB:1EYQ"
FT STRAND 17..20
FT /evidence="ECO:0007829|PDB:1EYQ"
FT TURN 22..24
FT /evidence="ECO:0007829|PDB:1EYQ"
FT STRAND 27..40
FT /evidence="ECO:0007829|PDB:1EYQ"
FT STRAND 43..55
FT /evidence="ECO:0007829|PDB:1EYQ"
FT HELIX 58..66
FT /evidence="ECO:0007829|PDB:1EYQ"
FT HELIX 71..75
FT /evidence="ECO:0007829|PDB:1EYQ"
FT HELIX 78..86
FT /evidence="ECO:0007829|PDB:1EYQ"
FT STRAND 87..89
FT /evidence="ECO:0007829|PDB:1FM8"
FT STRAND 91..99
FT /evidence="ECO:0007829|PDB:1EYQ"
FT HELIX 103..120
FT /evidence="ECO:0007829|PDB:1EYQ"
FT HELIX 126..139
FT /evidence="ECO:0007829|PDB:1EYQ"
FT STRAND 142..144
FT /evidence="ECO:0007829|PDB:1JX1"
FT STRAND 149..155
FT /evidence="ECO:0007829|PDB:1EYQ"
FT TURN 156..158
FT /evidence="ECO:0007829|PDB:1EYQ"
FT STRAND 159..169
FT /evidence="ECO:0007829|PDB:1EYQ"
FT STRAND 175..179
FT /evidence="ECO:0007829|PDB:1EYQ"
FT HELIX 181..192
FT /evidence="ECO:0007829|PDB:1EYQ"
FT HELIX 200..214
FT /evidence="ECO:0007829|PDB:1EYQ"
SQ SEQUENCE 222 AA; 23826 MW; 7767A72084AB4800 CRC64;
MAASITAITV ENLEYPAVVT SPVTGKSYFL GGAGERGLTI EGNFIKFTAI GVYLEDIAVA
SLAAKWKGKS SEELLETLDF YRDIISGPFE KLIRGSKIRE LSGPEYSRKV MENCVAHLKS
VGTYGDAEAE AMQKFAEAFK PVNFPPGASV FYRQSPDGIL GLSFSPDTSI PEKEAALIEN
KAVSSAVLET MIGEHAVSPD LKRCLAARLP ALLNEGAFKI GN
