ID   PHI_METAM               Reviewed;         181 AA.
AC   Q9S0X3;
DT   10-MAY-2005, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   03-AUG-2022, entry version 55.
DE   RecName: Full=3-hexulose-6-phosphate isomerase;
DE            EC=5.3.1.27;
DE   AltName: Full=6-phospho-3-hexuloisomerase;
DE            Short=PHI;
GN   Name=rmpB;
OS   Methylomonas aminofaciens.
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Methylococcales;
OC   Methylococcaceae; Methylomonas.
OX   NCBI_TaxID=46896;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], PROTEIN SEQUENCE OF 1-20, FUNCTION, AND
RP   SUBUNIT.
RC   STRAIN=77a;
RX   PubMed=10418139; DOI=10.1111/j.1574-6968.1999.tb13652.x;
RA   Sakai Y., Mitsui R., Katayama Y., Yanase H., Kato N.;
RT   "Organization of the genes involved in the ribulose monophosphate pathway
RT   in an obligate methylotrophic bacterium, Methylomonas aminofaciens 77a.";
RL   FEMS Microbiol. Lett. 176:125-130(1999).
CC   -!- FUNCTION: Catalyzes the isomerization between 3-hexulose 6-phosphate
CC       and fructose 6-phosphate. {ECO:0000269|PubMed:10418139}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=D-arabino-hex-3-ulose 6-phosphate = beta-D-fructose 6-
CC         phosphate; Xref=Rhea:RHEA:25900, ChEBI:CHEBI:57634,
CC         ChEBI:CHEBI:58542; EC=5.3.1.27;
CC   -!- PATHWAY: One-carbon metabolism; formaldehyde assimilation via RuMP
CC       pathway; D-fructose 6-phosphate from D-ribulose 5-phosphate and
CC       formaldehyde: step 2/2.
CC   -!- SUBUNIT: Homodimer. {ECO:0000269|PubMed:10418139}.
CC   -!- SIMILARITY: Belongs to the SIS family. PHI subfamily. {ECO:0000305}.
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DR   EMBL; AB026428; BAA83098.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q9S0X3; -.
DR   SMR; Q9S0X3; -.
DR   BRENDA; 5.3.1.27; 7933.
DR   UniPathway; UPA00294; UER00435.
DR   GO; GO:0097367; F:carbohydrate derivative binding; IEA:InterPro.
DR   GO; GO:0043800; F:hexulose-6-phosphate isomerase activity; IEA:UniProtKB-EC.
DR   GO; GO:1901135; P:carbohydrate derivative metabolic process; IEA:InterPro.
DR   GO; GO:0005975; P:carbohydrate metabolic process; IEA:UniProtKB-KW.
DR   GO; GO:0019647; P:formaldehyde assimilation via ribulose monophosphate cycle; IEA:UniProtKB-UniPathway.
DR   CDD; cd05005; SIS_PHI; 1.
DR   InterPro; IPR017552; PHI/rmpB.
DR   InterPro; IPR001347; SIS_dom.
DR   InterPro; IPR046348; SIS_dom_sf.
DR   PANTHER; PTHR43443; PTHR43443; 1.
DR   Pfam; PF01380; SIS; 1.
DR   SUPFAM; SSF53697; SSF53697; 1.
DR   PROSITE; PS51464; SIS; 1.
PE   1: Evidence at protein level;
KW   Carbohydrate metabolism; Direct protein sequencing; Isomerase.
FT   CHAIN           1..181
FT                   /note="3-hexulose-6-phosphate isomerase"
FT                   /id="PRO_0000136567"
FT   DOMAIN          27..168
FT                   /note="SIS"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00797"
FT   ACT_SITE        148
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255"
FT   BINDING         45
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255"
FT   BINDING         84..89
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   181 AA;  19345 MW;  FE9AE4FDFAB13AB7 CRC64;
     MNKYQELVVS KLTNVINNTA EGYDDKILSL VDAAGRTFIG GAGRSLLVSR FFAMRLVHAG
     YQVSMVGEVV TPSIQAGDLF IVISGSGSTE TLMPLVKKAK SQGAKIIVIS MKAQSPMAEL
     ADLVVPVGGN DANAFDKTHG MPMGTIFELS TLWFLEATIA KLVDQKGLTE EGMRAIHANL
     E