AC   MF_01166;
DC   Protein; auto
TR   HAMAP; MF_01166; -; 1; level=0
XX
Names: ArnA
XX
ID   ARNA
DE   RecName: Full=Bifunctional polymyxin resistance protein ArnA;
DE   Includes:
DE     RecName: Full=UDP-4-amino-4-deoxy-L-arabinose formyltransferase;
DE              EC=2.1.2.13;
DE     AltName: Full=ArnAFT;
DE     AltName: Full=UDP-L-Ara4N formyltransferase;
DE   Includes:
DE     RecName: Full=UDP-glucuronic acid oxidase, UDP-4-keto-hexauronic acid decarboxylating;
DE              EC=1.1.1.305;
DE     AltName: Full=ArnADH;
DE     AltName: Full=UDP-GlcUA decarboxylase;
DE     AltName: Full=UDP-glucuronic acid dehydrogenase;
GN   Name=arnA;
XX
CC   -!- FUNCTION: Bifunctional enzyme that catalyzes the oxidative
CC       decarboxylation of UDP-glucuronic acid (UDP-GlcUA) to UDP-4-keto-
CC       arabinose (UDP-Ara4O) and the addition of a formyl group to UDP-4-
CC       amino-4-deoxy-L-arabinose (UDP-L-Ara4N) to form UDP-L-4-formamido-
CC       arabinose (UDP-L-Ara4FN). The modified arabinose is attached to lipid A
CC       and is required for resistance to polymyxin and cationic antimicrobial
CC       peptides.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=NAD(+) + UDP-alpha-D-glucuronate = CO2 + NADH + UDP-beta-L-
CC         threo-pentopyranos-4-ulose; Xref=Rhea:RHEA:24702, ChEBI:CHEBI:16526,
CC         ChEBI:CHEBI:57540, ChEBI:CHEBI:57945, ChEBI:CHEBI:58052,
CC         ChEBI:CHEBI:58710; EC=1.1.1.305;
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=(6R)-10-formyltetrahydrofolate + UDP-4-amino-4-deoxy-beta-L-
CC         arabinose = (6S)-5,6,7,8-tetrahydrofolate + H(+) + UDP-4-deoxy-4-
CC         formamido-beta-L-arabinose; Xref=Rhea:RHEA:24706, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:57453, ChEBI:CHEBI:58708, ChEBI:CHEBI:58709,
CC         ChEBI:CHEBI:195366; EC=2.1.2.13;
CC   -!- PATHWAY: Nucleotide-sugar biosynthesis; UDP-4-deoxy-4-formamido-beta-L-
CC       arabinose biosynthesis; UDP-4-deoxy-4-formamido-beta-L-arabinose from
CC       UDP-alpha-D-glucuronate: step 1/3.
CC   -!- PATHWAY: Nucleotide-sugar biosynthesis; UDP-4-deoxy-4-formamido-beta-L-
CC       arabinose biosynthesis; UDP-4-deoxy-4-formamido-beta-L-arabinose from
CC       UDP-alpha-D-glucuronate: step 3/3.
CC   -!- PATHWAY: Bacterial outer membrane biogenesis; lipopolysaccharide
CC       biosynthesis.
CC   -!- SUBUNIT: Homohexamer, formed by a dimer of trimers.
CC   -!- SIMILARITY: In the N-terminal section; belongs to the Fmt family. UDP-
CC       L-Ara4N formyltransferase subfamily.
CC   -!- SIMILARITY: In the C-terminal section; belongs to the NAD(P)-dependent
CC       epimerase/dehydratase family. UDP-glucuronic acid decarboxylase
CC       subfamily.
XX
DR   Pfam; PF02911; Formyl_trans_C; 1; trigger=no
DR   Pfam; PF00551; Formyl_trans_N; 1; trigger=no
DR   Pfam; PF01370; Epimerase; 1; trigger=no
XX
KW   Antibiotic resistance
KW   Lipid A biosynthesis
KW   Lipid biosynthesis
KW   Lipid metabolism
KW   Lipopolysaccharide biosynthesis
KW   Multifunctional enzyme
KW   NAD
KW   Oxidoreductase
KW   Transferase
XX
GO   GO:0016616; F:oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor
GO   GO:0016742; F:hydroxymethyl-, formyl- and related transferase activity
GO   GO:0046493; P:lipid A metabolic process
XX
FT   From: ARNA_ECOLI (P77398)
FT   BINDING         368..369
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT   Condition: D-[IV]
FT   REGION          Nter..304
FT                   /note="Formyltransferase ArnAFT"
FT   BINDING         86..88
FT                   /ligand="(6R)-10-formyltetrahydrofolate"
FT                   /ligand_id="ChEBI:CHEBI:195366"
FT   Optional; Condition: H-x-I
FT   BINDING         136..140
FT                   /ligand="(6R)-10-formyltetrahydrofolate"
FT                   /ligand_id="ChEBI:CHEBI:195366"
FT   Condition: [VIT]-x(3)-D
FT   REGION          314..Cter
FT                   /note="Dehydrogenase ArnADH"
FT   BINDING         432..433
FT                   /ligand="UDP-alpha-D-glucuronate"
FT                   /ligand_id="ChEBI:CHEBI:58052"
FT   Condition: T-S
FT   BINDING         526..535
FT                   /ligand="UDP-alpha-D-glucuronate"
FT                   /ligand_id="ChEBI:CHEBI:58052"
FT   Condition: [KRQ]-x(6)-Q-x-R
FT   ACT_SITE        104
FT                   /note="Proton donor; for formyltransferase activity"
FT   Condition: H
FT   ACT_SITE        434
FT                   /note="Proton acceptor; for decarboxylase activity"
FT   Condition: E
FT   ACT_SITE        619
FT                   /note="Proton donor; for decarboxylase activity"
FT   Condition: R
FT   BINDING         114
FT                   /ligand="(6R)-10-formyltetrahydrofolate"
FT                   /ligand_id="ChEBI:CHEBI:195366"
FT   Condition: R
FT   BINDING         347
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT   Condition: D
FT   BINDING         393
FT                   /ligand="UDP-alpha-D-glucuronate"
FT                   /ligand_id="ChEBI:CHEBI:58052"
FT   Condition: A
FT   BINDING         398
FT                   /ligand="UDP-alpha-D-glucuronate"
FT                   /ligand_id="ChEBI:CHEBI:58052"
FT   Condition: Y
FT   BINDING         460
FT                   /ligand="UDP-alpha-D-glucuronate"
FT                   /ligand_id="ChEBI:CHEBI:58052"
FT   Condition: R
FT   BINDING         492
FT                   /ligand="UDP-alpha-D-glucuronate"
FT                   /ligand_id="ChEBI:CHEBI:58052"
FT   Condition: N
FT   BINDING         613
FT                   /ligand="UDP-alpha-D-glucuronate"
FT                   /ligand_id="ChEBI:CHEBI:58052"
FT   Condition: Y
FT   SITE            102
FT                   /note="Transition state stabilizer"
FT   Condition: N
FT   SITE            140
FT                   /note="Raises pKa of active site His"
FT   Condition: D
XX
Size: 654-687;
Related: MF_00182;
Template: P77398; O52325;
Scope:
 Bacteria; Gammaproteobacteria
Fusion:
 Nter: None
 Cter: None
Duplicate: None
Plasmid: None
Comments: None
XX
# Revision 1.33 2023/07/18
//