ID ILVC_BUCMH Reviewed; 490 AA.
AC Q9RQ47;
DT 29-AUG-2001, integrated into UniProtKB/Swiss-Prot.
DT 01-MAY-2000, sequence version 1.
DT 13-SEP-2023, entry version 106.
DE RecName: Full=Ketol-acid reductoisomerase (NADP(+)) {ECO:0000255|HAMAP-Rule:MF_00435};
DE Short=KARI {ECO:0000255|HAMAP-Rule:MF_00435};
DE EC=1.1.1.86 {ECO:0000255|HAMAP-Rule:MF_00435};
DE AltName: Full=Acetohydroxy-acid isomeroreductase {ECO:0000255|HAMAP-Rule:MF_00435};
DE Short=AHIR {ECO:0000255|HAMAP-Rule:MF_00435};
DE AltName: Full=Alpha-keto-beta-hydroxylacyl reductoisomerase {ECO:0000255|HAMAP-Rule:MF_00435};
DE AltName: Full=Ketol-acid reductoisomerase type 2 {ECO:0000255|HAMAP-Rule:MF_00435};
DE AltName: Full=Ketol-acid reductoisomerase type II {ECO:0000255|HAMAP-Rule:MF_00435};
GN Name=ilvC {ECO:0000255|HAMAP-Rule:MF_00435};
OS Buchnera aphidicola subsp. Melaphis rhois.
OC Bacteria; Pseudomonadota; Gammaproteobacteria; Enterobacterales;
OC Erwiniaceae; Buchnera.
OX NCBI_TaxID=118103;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=10555290; DOI=10.1093/oxfordjournals.molbev.a026071;
RA Clark M.A., Moran N.A., Baumann P.;
RT "Sequence evolution in bacterial endosymbionts having extreme base
RT compositions.";
RL Mol. Biol. Evol. 16:1586-1598(1999).
CC -!- FUNCTION: Involved in the biosynthesis of branched-chain amino acids
CC (BCAA). Catalyzes an alkyl-migration followed by a ketol-acid reduction
CC of (S)-2-acetolactate (S2AL) to yield (R)-2,3-dihydroxy-isovalerate. In
CC the isomerase reaction, S2AL is rearranged via a Mg-dependent methyl
CC migration to produce 3-hydroxy-3-methyl-2-ketobutyrate (HMKB). In the
CC reductase reaction, this 2-ketoacid undergoes a metal-dependent
CC reduction by NADPH to yield (R)-2,3-dihydroxy-isovalerate.
CC {ECO:0000255|HAMAP-Rule:MF_00435}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(2R)-2,3-dihydroxy-3-methylbutanoate + NADP(+) = (2S)-2-
CC acetolactate + H(+) + NADPH; Xref=Rhea:RHEA:22068, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:49072, ChEBI:CHEBI:57783, ChEBI:CHEBI:58349,
CC ChEBI:CHEBI:58476; EC=1.1.1.86; Evidence={ECO:0000255|HAMAP-
CC Rule:MF_00435};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(2R,3R)-2,3-dihydroxy-3-methylpentanoate + NADP(+) = (S)-2-
CC ethyl-2-hydroxy-3-oxobutanoate + H(+) + NADPH; Xref=Rhea:RHEA:13493,
CC ChEBI:CHEBI:15378, ChEBI:CHEBI:49256, ChEBI:CHEBI:49258,
CC ChEBI:CHEBI:57783, ChEBI:CHEBI:58349; EC=1.1.1.86;
CC Evidence={ECO:0000255|HAMAP-Rule:MF_00435};
CC -!- COFACTOR:
CC Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC Evidence={ECO:0000255|HAMAP-Rule:MF_00435};
CC Note=Binds 2 magnesium ions per subunit. {ECO:0000255|HAMAP-
CC Rule:MF_00435};
CC -!- PATHWAY: Amino-acid biosynthesis; L-isoleucine biosynthesis; L-
CC isoleucine from 2-oxobutanoate: step 2/4. {ECO:0000255|HAMAP-
CC Rule:MF_00435}.
CC -!- PATHWAY: Amino-acid biosynthesis; L-valine biosynthesis; L-valine from
CC pyruvate: step 2/4. {ECO:0000255|HAMAP-Rule:MF_00435}.
CC -!- SIMILARITY: Belongs to the ketol-acid reductoisomerase family.
CC {ECO:0000255|HAMAP-Rule:MF_00435}.
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DR EMBL; AF130814; AAF13807.1; -; Genomic_DNA.
DR AlphaFoldDB; Q9RQ47; -.
DR SMR; Q9RQ47; -.
DR UniPathway; UPA00047; UER00056.
DR UniPathway; UPA00049; UER00060.
DR GO; GO:0004455; F:ketol-acid reductoisomerase activity; IEA:UniProtKB-UniRule.
DR GO; GO:0000287; F:magnesium ion binding; IEA:UniProtKB-UniRule.
DR GO; GO:0009097; P:isoleucine biosynthetic process; IEA:UniProtKB-UniRule.
DR GO; GO:0009099; P:valine biosynthetic process; IEA:UniProtKB-UniRule.
DR Gene3D; 3.40.50.720; NAD(P)-binding Rossmann-like Domain; 1.
DR HAMAP; MF_00435; IlvC; 1.
DR InterPro; IPR008927; 6-PGluconate_DH-like_C_sf.
DR InterPro; IPR013328; 6PGD_dom2.
DR InterPro; IPR013023; KARI.
DR InterPro; IPR000506; KARI_C.
DR InterPro; IPR013116; KARI_N.
DR InterPro; IPR036291; NAD(P)-bd_dom_sf.
DR NCBIfam; TIGR00465; ilvC; 1.
DR PANTHER; PTHR21371; KETOL-ACID REDUCTOISOMERASE, MITOCHONDRIAL; 1.
DR PANTHER; PTHR21371:SF1; KETOL-ACID REDUCTOISOMERASE, MITOCHONDRIAL; 1.
DR Pfam; PF01450; IlvC; 2.
DR Pfam; PF07991; IlvN; 1.
DR SUPFAM; SSF48179; 6-phosphogluconate dehydrogenase C-terminal domain-like; 2.
DR SUPFAM; SSF51735; NAD(P)-binding Rossmann-fold domains; 1.
DR PROSITE; PS51851; KARI_C; 2.
DR PROSITE; PS51850; KARI_N; 1.
PE 3: Inferred from homology;
KW Amino-acid biosynthesis; Branched-chain amino acid biosynthesis; Magnesium;
KW Metal-binding; NADP; Oxidoreductase; Repeat.
FT CHAIN 1..490
FT /note="Ketol-acid reductoisomerase (NADP(+))"
FT /id="PRO_0000151290"
FT DOMAIN 15..208
FT /note="KARI N-terminal Rossmann"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01197"
FT DOMAIN 209..344
FT /note="KARI C-terminal knotted 1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01198"
FT DOMAIN 345..484
FT /note="KARI C-terminal knotted 2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01198"
FT ACT_SITE 132
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 45..48
FT /ligand="NADP(+)"
FT /ligand_id="ChEBI:CHEBI:58349"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 68
FT /ligand="NADP(+)"
FT /ligand_id="ChEBI:CHEBI:58349"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 78
FT /ligand="NADP(+)"
FT /ligand_id="ChEBI:CHEBI:58349"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 108..110
FT /ligand="NADP(+)"
FT /ligand_id="ChEBI:CHEBI:58349"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 158
FT /ligand="NADP(+)"
FT /ligand_id="ChEBI:CHEBI:58349"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 217
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /ligand_label="1"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 217
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /ligand_label="2"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 221
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /ligand_label="1"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 389
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /ligand_label="2"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 393
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /ligand_label="2"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
FT BINDING 414
FT /ligand="substrate"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00435"
SQ SEQUENCE 490 AA; 55564 MW; 0389DD44B6A856B1 CRC64;
MKNYFNSLNF RQKLINLQKC KLIDNQFLSE KNNVLKGKNI VIVGCGSQGL NQGLNMRDSG
LNISYALRDD SIFNKNQSWI NATSNGFFVG TYENIIPTAD LVINLTPDKQ HEQVVNVLQK
FMKPNSVLGF SHGFNIVEVG QLIRNDITVI MVAPKCPGTE VREEYKRGFG VPALIAVHSE
NDPHDIGFEI AKSWAISIGS HHAGILHSSF IAEVKSDLMG EQTILCGMLQ ASSLVCYNQL
IFQGVNPSYA GKLIQTGWEV ITESVKHGGI TLMLDRLSNT AKIRAYFLSK KLKKIFFPLF
RKHMDDIISG EFSKNMMFDW KNNDQQLKEW RTEIQNTDFE KCNIYYKQIP EQEYFDNGLL
MVAILKAGIE LSFEIMIETG IKEESAYYES LHELPLIANT IARKRLYEMN LVISDTAEYG
SYLFSHAAIP LLKKFMNELQ PGDLGNKIST SELDNITLYK VNAKIESHPI EIIGKKLRLY
MTSMVPIKTK
//
