ID   PANB_BART1              Reviewed;         271 AA.
AC   A9IRP2;
DT   20-MAY-2008, integrated into UniProtKB/Swiss-Prot.
DT   05-FEB-2008, sequence version 1.
DT   04-NOV-2026, entry version 96.
DE   RecName: Full=3-methyl-2-oxobutanoate hydroxymethyltransferase {ECO:0000255|HAMAP-Rule:MF_00156};
DE            EC=2.1.2.11 {ECO:0000255|HAMAP-Rule:MF_00156};
DE   AltName: Full=Ketopantoate hydroxymethyltransferase {ECO:0000255|HAMAP-Rule:MF_00156};
DE            Short=KPHMT {ECO:0000255|HAMAP-Rule:MF_00156};
GN   Name=panB {ECO:0000255|HAMAP-Rule:MF_00156};
GN   OrderedLocusNames=BT_0790;
OS   Bartonella tribocorum (strain DSM 28219 / CCUG 45778 / CIP 105476 / IBS
OS   506).
OC   Bacteria; Pseudomonadati; Pseudomonadota; Alphaproteobacteria;
OC   Hyphomicrobiales; Bartonellaceae; Bartonella.
OX   NCBI_TaxID=382640;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=DSM 28219 / CCUG 45778 / CIP 105476 / IBS 506;
RX   PubMed=18037886; DOI=10.1038/ng.2007.38;
RA   Saenz H.L., Engel P., Stoeckli M.C., Lanz C., Raddatz G.,
RA   Vayssier-Taussat M., Birtles R., Schuster S.C., Dehio C.;
RT   "Genomic analysis of Bartonella identifies type IV secretion systems as
RT   host adaptability factors.";
RL   Nat. Genet. 39:1469-1476(2007).
CC   -!- FUNCTION: Catalyzes the reversible reaction in which hydroxymethyl
CC       group from 5,10-methylenetetrahydrofolate is transferred onto alpha-
CC       ketoisovalerate to form ketopantoate. {ECO:0000255|HAMAP-
CC       Rule:MF_00156}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=(6R)-5,10-methylene-5,6,7,8-tetrahydrofolate + 3-methyl-2-
CC         oxobutanoate + H2O = 2-dehydropantoate + (6S)-5,6,7,8-
CC         tetrahydrofolate; Xref=Rhea:RHEA:11824, ChEBI:CHEBI:11561,
CC         ChEBI:CHEBI:11851, ChEBI:CHEBI:15377, ChEBI:CHEBI:15636,
CC         ChEBI:CHEBI:57453; EC=2.1.2.11; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_00156};
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_00156};
CC       Note=Binds 1 Mg(2+) ion per subunit. {ECO:0000255|HAMAP-Rule:MF_00156};
CC   -!- PATHWAY: Cofactor biosynthesis; (R)-pantothenate biosynthesis; (R)-
CC       pantoate from 3-methyl-2-oxobutanoate: step 1/2. {ECO:0000255|HAMAP-
CC       Rule:MF_00156}.
CC   -!- SUBUNIT: Homodecamer; pentamer of dimers. {ECO:0000255|HAMAP-
CC       Rule:MF_00156}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000255|HAMAP-Rule:MF_00156}.
CC   -!- SIMILARITY: Belongs to the PanB family. {ECO:0000255|HAMAP-
CC       Rule:MF_00156}.
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; AM260525; CAK01205.1; -; Genomic_DNA.
DR   RefSeq; WP_012231318.1; NC_010161.1.
DR   SMR; A9IRP2; -.
DR   KEGG; btr:BT_0790; -.
DR   eggNOG; COG0413; Bacteria.
DR   HOGENOM; CLU_036645_1_0_5; -.
DR   OMA; AAEHAYW; -.
DR   UniPathway; UPA00028; UER00003.
DR   CDD; cd06557; KPHMT-like; 1.
DR   FunFam; 3.20.20.60:FF:000003; 3-methyl-2-oxobutanoate hydroxymethyltransferase; 1.
DR   Gene3D; 3.20.20.60; Phosphoenolpyruvate-binding domains; 1.
DR   HAMAP; MF_00156; PanB; 1.
DR   InterPro; IPR003700; Pantoate_hydroxy_MeTrfase.
DR   InterPro; IPR015813; Pyrv/PenolPyrv_kinase-like_dom.
DR   InterPro; IPR040442; Pyrv_kinase-like_dom_sf.
DR   PANTHER; PTHR20881; 3-METHYL-2-OXOBUTANOATE HYDROXYMETHYLTRANSFERASE; 1.
DR   PANTHER; PTHR20881:SF0; 3-METHYL-2-OXOBUTANOATE HYDROXYMETHYLTRANSFERASE; 1.
DR   Pfam; PF02548; Pantoate_transf; 1.
DR   PIRSF; PIRSF000388; Pantoate_hydroxy_MeTrfase; 1.
DR   SUPFAM; SSF51621; Phosphoenolpyruvate/pyruvate domain; 1.
DR   NCBIfam; TIGR00222; panB; 1.
DR   NCBIfam; NF001452; PRK00311.1; 1.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0003864; F:3-methyl-2-oxobutanoate hydroxymethyltransferase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0000287; F:magnesium ion binding; IEA:TreeGrafter.
DR   GO; GO:0015940; P:pantothenate biosynthetic process; IEA:UniProtKB-UniRule.
DR   Proteomes; UP000001592; Chromosome.
DR   AlphaFoldDB; A9IRP2; -.
PE   3: Inferred from homology;
KW   Cytoplasm; Magnesium; Metal-binding; Pantothenate biosynthesis;
KW   Reference proteome; Transferase.
FT   CHAIN           1..271
FT                   /note="3-methyl-2-oxobutanoate hydroxymethyltransferase"
FT                   /id="PRO_1000076816"
FT   ACT_SITE        187
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00156"
FT   BINDING         49..50
FT                   /ligand="3-methyl-2-oxobutanoate"
FT                   /ligand_id="ChEBI:CHEBI:11851"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00156"
FT   BINDING         49
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00156"
FT   BINDING         88
FT                   /ligand="3-methyl-2-oxobutanoate"
FT                   /ligand_id="ChEBI:CHEBI:11851"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00156"
FT   BINDING         88
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00156"
FT   BINDING         118
FT                   /ligand="3-methyl-2-oxobutanoate"
FT                   /ligand_id="ChEBI:CHEBI:11851"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00156"
FT   BINDING         120
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00156"
SQ   SEQUENCE   271 AA;  29641 MW;  E6ACDAF0D62DE642 CRC64;
     MSVHKMVKRI TSSQIRARKG QQPIVSLTAY QAYTARIADP YCDILLVGDS VGMVVYGFET
     TLPVNLDMMI LHGQAVVRGS QKALVVIDMP FGSYEESKEQ AFLNASRILA QTGCGAVKLE
     GGVYMAETID FLCKRGIPVM GHIGLTPQAV NRFGGFNTQG RKESDWQRIE DDAVVIENAG
     AFAIVLEGIV EPLAVKLTEK LSIPTIGIGA SNQCDGQVLV MEDMLGYGAH VPKFVRRYGD
     LEQAMETAIK NYAEDVTSRA FPAEKEVYKL K
//