ID   TENA_HELPX              Reviewed;         217 AA.
AC   A8KRL3;
DT   07-JAN-2015, integrated into UniProtKB/Swiss-Prot.
DT   04-DEC-2007, sequence version 1.
DT   03-AUG-2022, entry version 39.
DE   RecName: Full=Aminopyrimidine aminohydrolase {ECO:0000303|PubMed:19780837};
DE            EC=3.5.99.2 {ECO:0000269|PubMed:19780837};
GN   Name=tenA {ECO:0000303|PubMed:19780837};
OS   Helicobacter pylori (Campylobacter pylori).
OC   Bacteria; Proteobacteria; Epsilonproteobacteria; Campylobacterales;
OC   Helicobacteraceae; Helicobacter.
OX   NCBI_TaxID=210;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=DSM 4867 / CCUG 17874 / NCTC 11638;
RA   Barison N., Cendron L., Trento A., Angelini A., Zanotti G.;
RT   "The structural and functional characterization of HP1287 from Helicobacter
RT   pylori demonstrates it is a tenA homologue.";
RL   Submitted (OCT-2007) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   X-RAY CRYSTALLOGRAPHY (2.40 ANGSTROMS) OF WILD-TYPE AND MUTANT TYR-47,
RP   FUNCTION, CATALYTIC ACTIVITY, SUBSTRATE SPECIFICITY, BIOPHYSICOCHEMICAL
RP   PROPERTIES, SUBUNIT, AND MUTAGENESIS OF PHE-47.
RC   STRAIN=DSM 4867 / CCUG 17874 / NCTC 11638;
RX   PubMed=19780837; DOI=10.1111/j.1742-4658.2009.07326.x;
RA   Barison N., Cendron L., Trento A., Angelini A., Zanotti G.;
RT   "Structural and mutational analysis of TenA protein (HP1287) from the
RT   Helicobacter pylori thiamin salvage pathway - evidence of a different
RT   substrate specificity.";
RL   FEBS J. 276:6227-6235(2009).
CC   -!- FUNCTION: Catalyzes an amino-pyrimidine hydrolysis reaction at the C5'
CC       of the pyrimidine moiety of thiamine compounds to give a
CC       hydroxymethylpyrimidine (HMP). Displays low activity on 4-amino-5-
CC       aminomethyl-2-methylpyrimidine as substrate, indicating that the enzyme
CC       may act on a different HMP precursor that may derive from the human
CC       stomach food assumption or processing. Is probably involved in thiamine
CC       biosynthesis. Does not display thiaminase II activity, as it is unable
CC       to hydrolyze thiamine. {ECO:0000269|PubMed:19780837}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=4-amino-5-aminomethyl-2-methylpyrimidine + H2O = 4-amino-5-
CC         hydroxymethyl-2-methylpyrimidine + NH4(+); Xref=Rhea:RHEA:31799,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:16892, ChEBI:CHEBI:28938,
CC         ChEBI:CHEBI:63416; EC=3.5.99.2;
CC         Evidence={ECO:0000269|PubMed:19780837};
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         KM=58 uM for 4-amino-5-aminomethyl-2-methylpyrimidine
CC         {ECO:0000269|PubMed:19780837};
CC         Note=kcat is 1.7 min(-1) for the hydrolysis of 4-amino-5-aminomethyl-
CC         2-methylpyrimidine. {ECO:0000269|PubMed:19780837};
CC       pH dependence:
CC         Activity is lost at pH 6. {ECO:0000269|PubMed:19780837};
CC   -!- PATHWAY: Cofactor biosynthesis; thiamine diphosphate biosynthesis.
CC       {ECO:0000303|PubMed:19780837}.
CC   -!- SUBUNIT: Homotetramer. {ECO:0000269|PubMed:19780837}.
CC   -!- MISCELLANEOUS: H.pylori is expected to possess a reduced thiamine
CC       biosynthetic pathway. Some enzymes involved in de novo thiamine
CC       biosynthesis in other organisms, such as ThiO, ThiS and ThiG, are
CC       missing in this species. The very acidic environment of the stomach
CC       makes the accumulation of formylaminopyrimidine very unlikely because
CC       it is mainly a base-degraded derivative of thiamine;
CC       formylaminopyrimidine is the precursor identified in a thiamine salvage
CC       pathway in Bacillus species. {ECO:0000303|PubMed:19780837,
CC       ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the TenA family. {ECO:0000305}.
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DR   EMBL; AM900414; CAP12589.1; -; Genomic_DNA.
DR   RefSeq; WP_001198306.1; NZ_BNAZ01000048.1.
DR   PDB; 2RD3; X-ray; 2.70 A; A/D=1-217.
DR   PDB; 3IBX; X-ray; 2.40 A; A/D=1-217.
DR   PDBsum; 2RD3; -.
DR   PDBsum; 3IBX; -.
DR   AlphaFoldDB; A8KRL3; -.
DR   SMR; A8KRL3; -.
DR   STRING; 1345592.CBOM010000005_gene576; -.
DR   eggNOG; COG0819; Bacteria.
DR   UniPathway; UPA00060; -.
DR   EvolutionaryTrace; A8KRL3; -.
DR   GO; GO:0050334; F:thiaminase activity; IEA:UniProtKB-EC.
DR   GO; GO:0009228; P:thiamine biosynthetic process; IEA:UniProtKB-KW.
DR   GO; GO:0009229; P:thiamine diphosphate biosynthetic process; IEA:UniProtKB-UniPathway.
DR   Gene3D; 1.20.910.10; -; 1.
DR   InterPro; IPR016084; Haem_Oase-like_multi-hlx.
DR   InterPro; IPR004305; Thiaminase-2/PQQC.
DR   InterPro; IPR027574; Thiaminase_II.
DR   Pfam; PF03070; TENA_THI-4; 1.
DR   SUPFAM; SSF48613; SSF48613; 1.
DR   TIGRFAMs; TIGR04306; salvage_TenA; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Hydrolase; Thiamine biosynthesis.
FT   CHAIN           1..217
FT                   /note="Aminopyrimidine aminohydrolase"
FT                   /id="PRO_0000431514"
FT   ACT_SITE        135
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000250|UniProtKB:P25052"
FT   ACT_SITE        207
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000250|UniProtKB:P25052"
FT   BINDING         44
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:P25052"
FT   BINDING         139
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:P25052"
FT   BINDING         165
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:P25052"
FT   MUTAGEN         47
FT                   /note="F->Y: Activity remains very low with 4-amino-5-
FT                   aminomethyl-2-methylpyrimidine as substrate, and the
FT                   catalytic efficiency is even decreased by 33-fold."
FT   HELIX           3..19
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           22..29
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           34..61
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           65..79
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   TURN            81..84
FT                   /evidence="ECO:0007829|PDB:2RD3"
FT   HELIX           85..92
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           97..102
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           107..122
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           125..131
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           133..146
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   STRAND          149..151
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   TURN            152..154
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   TURN            156..158
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           159..164
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           168..184
FT                   /evidence="ECO:0007829|PDB:3IBX"
FT   HELIX           190..215
FT                   /evidence="ECO:0007829|PDB:3IBX"
SQ   SEQUENCE   217 AA;  25013 MW;  4E7B6D9ECF853739 CRC64;
     MQVSQYLYQN AQSIWGDCIS HPFVQGIGRG TLERDKFRFY IIQDYLFLLE YAKVFALGVV
     KACDEAVMRE FSNAIQDILN NEMSIHNHYI RELQITQKEL QNACPTLANK SYTSYMLAEG
     FKGSIKEVAA AVLSCGWSYL VIAQNLSQIP NALEHAFYGH WIKGYSSKEF QACVNWNINL
     LDSLTLASSK QEIEKLKEIF ITTSEYEYLF WDMAYQS