AC   MF_00156;
DC   Protein; auto
TR   HAMAP; MF_00156; -; 1; level=0
XX
Names: PanB
XX
ID   PANB
DE   RecName: Full=3-methyl-2-oxobutanoate hydroxymethyltransferase;
DE            EC=2.1.2.11;
DE   AltName: Full=Ketopantoate hydroxymethyltransferase;
DE            Short=KPHMT;
GN   Name=panB;
XX
CC   -!- FUNCTION: Catalyzes the reversible reaction in which hydroxymethyl
CC       group from 5,10-methylenetetrahydrofolate is transferred onto alpha-
CC       ketoisovalerate to form ketopantoate.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=(6R)-5,10-methylene-5,6,7,8-tetrahydrofolate + 3-methyl-2-
CC         oxobutanoate + H2O = (6S)-5,6,7,8-tetrahydrofolate + 2-
CC         dehydropantoate; 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;
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC       Note=Binds 1 Mg(2+) ion per subunit.;
case <OC:Bacteria>
CC   -!- PATHWAY: Cofactor biosynthesis; (R)-pantothenate biosynthesis; (R)-
CC       pantoate from 3-methyl-2-oxobutanoate: step 1/2.
else case <OC:Archaea>
CC   -!- PATHWAY: Cofactor biosynthesis; coenzyme A biosynthesis.
end case
CC   -!- SUBUNIT: Homodecamer; pentamer of dimers.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm.
CC   -!- SIMILARITY: Belongs to the PanB family.
XX
DR   Pfam; PF02548; Pantoate_transf; 1; trigger=no
DR   PRINTS; PR01415; ANKYRIN; 1; trigger=no
DR   NCBIfam; TIGR00222; PanB; 1; trigger=no
XX
KW   Cytoplasm
KW   Magnesium
KW   Metal-binding
case <OC:Bacteria>
KW   Pantothenate biosynthesis
else case <OC:Archaea>
KW   Coenzyme A biosynthesis
end case
KW   Transferase
XX
GO   GO:0003864; F:3-methyl-2-oxobutanoate hydroxymethyltransferase activity
case <OC:Bacteria>
GO   GO:0015940; P:pantothenate biosynthetic process
else case <OC:Archaea>
GO   GO:0015937; P:coenzyme A biosynthetic process
end case
GO   GO:0005737; C:cytoplasm
XX
FT   From: PANB_ECOLI (P31057)
FT   BINDING         45..46
FT                   /ligand="3-methyl-2-oxobutanoate"
FT                   /ligand_id="ChEBI:CHEBI:11851"
FT   ACT_SITE        181
FT                   /note="Proton acceptor"
FT   Condition: E
FT   BINDING         45
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT   Condition: D
FT   BINDING         84
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT   Condition: D
FT   BINDING         114
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT   Condition: E
FT   BINDING         84
FT                   /ligand="3-methyl-2-oxobutanoate"
FT                   /ligand_id="ChEBI:CHEBI:11851"
FT   Condition: D
FT   BINDING         112
FT                   /ligand="3-methyl-2-oxobutanoate"
FT                   /ligand_id="ChEBI:CHEBI:11851"
FT   Condition: K
XX
Size: 257-326;
Related: None;
Template: P9WIL7; P31057; Q9X712; Q9JZW6;
Scope:
 Bacteria
 Archaea
Fusion:
 Nter: None
 Cter: None
Duplicate: in BRADU, BURCH, BURCM, BURL3, HAHCH, METPP, PSEAB, PSEAE, PSEE4,
 PSEF5, ALIF1, ZYMMO
Plasmid: in RHIEC, RHIJ3, RUEST
Comments: Most archaea utilize a modified route for coenzyme A biosynthesis. PoK and PPS
 replace PS and PanK (used by bacteria and eukaryotes) in the conversion of pantoate to
 4'-phosphopantothenate. See PubMed=31337720.
XX
# Revision 1.43 2023/11/28
//