ID   GUAC_BUCAP              Reviewed;         349 AA.
AC   Q8K9U0;
DT   08-NOV-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2002, sequence version 1.
DT   03-AUG-2022, entry version 113.
DE   RecName: Full=GMP reductase {ECO:0000255|HAMAP-Rule:MF_00596};
DE            EC=1.7.1.7 {ECO:0000255|HAMAP-Rule:MF_00596};
DE   AltName: Full=Guanosine 5'-monophosphate oxidoreductase {ECO:0000255|HAMAP-Rule:MF_00596};
DE            Short=Guanosine monophosphate reductase {ECO:0000255|HAMAP-Rule:MF_00596};
GN   Name=guaC {ECO:0000255|HAMAP-Rule:MF_00596}; OrderedLocusNames=BUsg_198;
OS   Buchnera aphidicola subsp. Schizaphis graminum (strain Sg).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=198804;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Sg;
RX   PubMed=12089438; DOI=10.1126/science.1071278;
RA   Tamas I., Klasson L., Canbaeck B., Naeslund A.K., Eriksson A.-S.,
RA   Wernegreen J.J., Sandstroem J.P., Moran N.A., Andersson S.G.E.;
RT   "50 million years of genomic stasis in endosymbiotic bacteria.";
RL   Science 296:2376-2379(2002).
CC   -!- FUNCTION: Catalyzes the irreversible NADPH-dependent deamination of GMP
CC       to IMP. It functions in the conversion of nucleobase, nucleoside and
CC       nucleotide derivatives of G to A nucleotides, and in maintaining the
CC       intracellular balance of A and G nucleotides. {ECO:0000255|HAMAP-
CC       Rule:MF_00596}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=IMP + NADP(+) + NH4(+) = GMP + 2 H(+) + NADPH;
CC         Xref=Rhea:RHEA:17185, ChEBI:CHEBI:15378, ChEBI:CHEBI:28938,
CC         ChEBI:CHEBI:57783, ChEBI:CHEBI:58053, ChEBI:CHEBI:58115,
CC         ChEBI:CHEBI:58349; EC=1.7.1.7; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_00596};
CC   -!- SUBUNIT: Homotetramer. {ECO:0000255|HAMAP-Rule:MF_00596}.
CC   -!- SIMILARITY: Belongs to the IMPDH/GMPR family. GuaC type 1 subfamily.
CC       {ECO:0000255|HAMAP-Rule:MF_00596}.
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DR   EMBL; AE013218; AAM67762.1; -; Genomic_DNA.
DR   RefSeq; WP_011053729.1; NC_004061.1.
DR   AlphaFoldDB; Q8K9U0; -.
DR   SMR; Q8K9U0; -.
DR   STRING; 198804.BUsg_198; -.
DR   EnsemblBacteria; AAM67762; AAM67762; BUsg_198.
DR   KEGG; bas:BUsg_198; -.
DR   eggNOG; COG0516; Bacteria.
DR   HOGENOM; CLU_022552_5_3_6; -.
DR   OMA; AYKEYFG; -.
DR   OrthoDB; 532857at2; -.
DR   Proteomes; UP000000416; Chromosome.
DR   GO; GO:1902560; C:GMP reductase complex; IEA:InterPro.
DR   GO; GO:0003920; F:GMP reductase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0006163; P:purine nucleotide metabolic process; IEA:UniProtKB-UniRule.
DR   CDD; cd00381; IMPDH; 1.
DR   Gene3D; 3.20.20.70; -; 1.
DR   HAMAP; MF_00596; GMP_reduct_type1; 1.
DR   InterPro; IPR013785; Aldolase_TIM.
DR   InterPro; IPR005993; GMPR.
DR   InterPro; IPR015875; IMP_DH/GMP_Rdtase_CS.
DR   InterPro; IPR001093; IMP_DH_GMPRt.
DR   Pfam; PF00478; IMPDH; 1.
DR   PIRSF; PIRSF000235; GMP_reductase; 1.
DR   TIGRFAMs; TIGR01305; GMP_reduct_1; 1.
DR   PROSITE; PS00487; IMP_DH_GMP_RED; 1.
PE   3: Inferred from homology;
KW   Metal-binding; NADP; Oxidoreductase; Potassium.
FT   CHAIN           1..349
FT                   /note="GMP reductase"
FT                   /id="PRO_0000093733"
FT   ACT_SITE        186
FT                   /note="Thioimidate intermediate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00596"
FT   BINDING         108..131
FT                   /ligand="NADP(+)"
FT                   /ligand_id="ChEBI:CHEBI:58349"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00596"
FT   BINDING         181
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00596"
FT   BINDING         183
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00596"
FT   BINDING         216..239
FT                   /ligand="NADP(+)"
FT                   /ligand_id="ChEBI:CHEBI:58349"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00596"
SQ   SEQUENCE   349 AA;  38618 MW;  D5CCF618376665CF CRC64;
     MRIEEDIKLG FKDVLIRPKR STLKSRSEVN LIRCFSFKYS TMKWFGIPLI AANMDTIGTF
     RMAEALSKFN ILTAVHKYYS FDEWKNFISV SSKEILEHVI VSIGTSNLDF FKIKKIFSLS
     SELKYICIDV ANGYSEHFVS FLKKIRSFFP DKIICAGNVV TGEMVEELIL SGADIVKVGI
     GPGSVCTTRL KTGIGYPQLS AIIECADAAH GLNGQIISDG GCTVSGDIAK AFGGGADFVM
     LGGMFAGHTE CLGEIIQEKS KKFMLFYGMS STSAMKRYTG KIPGYRASEG KIVKIPFRGN
     VDVTVRDILG GLRSSCTYVG AQKLKELTKR TTFIRVSEQE NCIFNNFKN