ID   TSOXB_CORS1             Reviewed;         405 AA.
AC   P40875; Q46335;
DT   01-FEB-1995, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1997, sequence version 2.
DT   04-NOV-2026, entry version 122.
DE   RecName: Full=Sarcosine oxidase subunit beta {ECO:0000305};
DE            Short=Sarcosine oxidase subunit B {ECO:0000305};
DE            EC=1.5.3.24 {ECO:0000269|PubMed:3427080, ECO:0000269|PubMed:9185627, ECO:0000305|PubMed:11330998};
DE   AltName: Full=Sarcosine oxidase (5,10-methylenetetrahydrofolate-forming) subunit beta {ECO:0000305};
DE   AltName: Full=Tetrameric sarcosine oxidase subunit beta {ECO:0000305};
DE            Short=TSOX subunit beta {ECO:0000305};
GN   Name=soxB {ECO:0000303|PubMed:7543100};
OS   Corynebacterium sp. (strain P-1).
OC   Bacteria; Bacillati; Actinomycetota; Actinomycetes; Mycobacteriales;
OC   Corynebacteriaceae; Corynebacterium.
OX   NCBI_TaxID=69006;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], PROTEIN SEQUENCE OF 2-36, SUBUNIT, AND
RP   IDENTIFICATION BY MASS SPECTROMETRY.
RC   STRAIN=P-1;
RX   PubMed=7543100; DOI=10.1074/jbc.270.31.18252;
RA   Chlumsky L.J., Zhang L., Jorns M.S.;
RT   "Sequence analysis of sarcosine oxidase and nearby genes reveals homologies
RT   with key enzymes of folate one-carbon metabolism.";
RL   J. Biol. Chem. 270:18252-18259(1995).
RN   [2]
RP   PROTEIN SEQUENCE OF 173-178, FMN-BINDING AT HIS-173, COFACTOR,
RP   IDENTIFICATION BY MASS SPECTROMETRY, AND MUTAGENESIS OF HIS-175.
RC   STRAIN=P-1;
RX   PubMed=9485355; DOI=10.1021/bi972705s;
RA   Chlumsky L.J., Sturgess A.W., Nieves E., Jorns M.S.;
RT   "Identification of the covalent flavin attachment site in sarcosine
RT   oxidase.";
RL   Biochemistry 37:2089-2095(1998).
RN   [3]
RP   FUNCTION, AND CATALYTIC ACTIVITY.
RC   STRAIN=P-1;
RX   PubMed=3427080; DOI=10.1021/bi00397a029;
RA   Kvalnes-Krick K., Jorns M.S.;
RT   "Interaction of tetrahydrofolate and other folate derivatives with
RT   bacterial sarcosine oxidase.";
RL   Biochemistry 26:7391-7395(1987).
RN   [4]
RP   FUNCTION, CATALYTIC ACTIVITY, SUBUNIT, AND SUBCELLULAR LOCATION.
RC   STRAIN=P-1;
RX   PubMed=7692961; DOI=10.1021/bi00092a024;
RA   Chlumsky L.J., Zhang L., Ramsey A.J., Jorns M.S.;
RT   "Preparation and properties of recombinant corynebacterial sarcosine
RT   oxidase: evidence for posttranslational modification during turnover with
RT   sarcosine.";
RL   Biochemistry 32:11132-11142(1993).
RN   [5]
RP   FMN-BINDING, AND COFACTOR.
RC   STRAIN=P-1;
RX   PubMed=8611516; DOI=10.1021/bi952995h;
RA   Willie A., Edmondson D.E., Jorns M.S.;
RT   "Sarcosine oxidase contains a novel covalently bound FMN.";
RL   Biochemistry 35:5292-5299(1996).
RN   [6]
RP   FUNCTION, AND CATALYTIC ACTIVITY.
RC   STRAIN=P-1;
RX   PubMed=9185627; DOI=10.1006/abbi.1997.0106;
RA   Wagner M.A., Schuman Jorns M.;
RT   "Folate utilization by monomeric versus heterotetrameric sarcosine
RT   oxidases.";
RL   Arch. Biochem. Biophys. 342:176-181(1997).
RN   [7]
RP   FUNCTION, CATALYTIC ACTIVITY, COFACTOR, FMN-BINDING AT HIS-173, SUBUNIT,
RP   AND MUTAGENESIS OF GLY-30; CYS-146; HIS-173; CYS-195 AND CYS-351.
RC   STRAIN=P-1;
RX   PubMed=11330998; DOI=10.1021/bi010101p;
RA   Eschenbrenner M., Chlumsky L.J., Khanna P., Strasser F., Jorns M.S.;
RT   "Organization of the multiple coenzymes and subunits and role of the
RT   covalent flavin link in the complex heterotetrameric sarcosine oxidase.";
RL   Biochemistry 40:5352-5367(2001).
CC   -!- FUNCTION: In the presence of tetrahydrofolate, catalyzes the oxidative
CC       demethylation of sarcosine to yield glycine, 5,10-
CC       methylenetetrahydrofolate and hydrogen peroxide (PubMed:11330998,
CC       PubMed:3427080, PubMed:9185627). In the absence of tetrahydrofolate,
CC       catalyzes the oxidative demethylation of sarcosine to yield glycine,
CC       formaldehyde and hydrogen peroxide (PubMed:11330998, PubMed:7692961,
CC       PubMed:9185627). {ECO:0000269|PubMed:11330998,
CC       ECO:0000269|PubMed:3427080, ECO:0000269|PubMed:7692961,
CC       ECO:0000269|PubMed:9185627}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=sarcosine + (6S)-5,6,7,8-tetrahydrofolate + O2 = (6R)-5,10-
CC         methylene-5,6,7,8-tetrahydrofolate + glycine + H2O2;
CC         Xref=Rhea:RHEA:70455, ChEBI:CHEBI:15379, ChEBI:CHEBI:15636,
CC         ChEBI:CHEBI:16240, ChEBI:CHEBI:57305, ChEBI:CHEBI:57433,
CC         ChEBI:CHEBI:57453; EC=1.5.3.24; Evidence={ECO:0000269|PubMed:3427080,
CC         ECO:0000269|PubMed:9185627, ECO:0000305|PubMed:11330998};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=sarcosine + O2 + H2O = glycine + formaldehyde + H2O2;
CC         Xref=Rhea:RHEA:13313, ChEBI:CHEBI:15377, ChEBI:CHEBI:15379,
CC         ChEBI:CHEBI:16240, ChEBI:CHEBI:16842, ChEBI:CHEBI:57305,
CC         ChEBI:CHEBI:57433; Evidence={ECO:0000269|PubMed:11330998,
CC         ECO:0000269|PubMed:7692961, ECO:0000269|PubMed:9185627};
CC   -!- COFACTOR:
CC       Name=FAD; Xref=ChEBI:CHEBI:57692;
CC         Evidence={ECO:0000305|PubMed:11330998};
CC       Note=Binds 1 FAD per subunit. {ECO:0000305|PubMed:11330998};
CC   -!- COFACTOR:
CC       Name=FMN; Xref=ChEBI:CHEBI:58210;
CC         Evidence={ECO:0000269|PubMed:11330998, ECO:0000269|PubMed:8611516,
CC         ECO:0000269|PubMed:9485355};
CC       Note=Binds 1 FMN covalently (PubMed:11330998, PubMed:8611516,
CC       PubMed:9485355). The covalent flavin was originally thought to be FAD.
CC       {ECO:0000269|PubMed:11330998, ECO:0000269|PubMed:8611516,
CC       ECO:0000269|PubMed:9485355, ECO:0000305|PubMed:8611516};
CC   -!- SUBUNIT: Heterotetramer composed of subunits alpha (SoxA), beta (SoxB),
CC       gamma (SoxG) and delta (SoxD) (PubMed:11330998, PubMed:7543100,
CC       PubMed:7692961). May bind to both the delta subunit and the alpha-gamma
CC       complex and thereby stabilizes the association of the delta subunit
CC       with the alpha-gamma complex (PubMed:11330998).
CC       {ECO:0000269|PubMed:11330998, ECO:0000269|PubMed:7543100,
CC       ECO:0000269|PubMed:7692961}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000269|PubMed:7692961}.
CC   -!- MISCELLANEOUS: Utilization of tetrahydrofolate is probably the
CC       physiological reaction since the products are substrates for serine
CC       hydroxymethyltransferase, an enzyme which is part of the sarcosine
CC       oxidase operon. {ECO:0000269|PubMed:9185627}.
CC   -!- SIMILARITY: Belongs to the SoxB family. {ECO:0000305}.
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DR   EMBL; U23955; AAC43459.1; -; Genomic_DNA.
DR   PIR; PX0049; PX0049.
DR   AlphaFoldDB; P40875; -.
DR   SMR; P40875; -.
DR   KEGG; ag:AAC43459; -.
DR   BioCyc; MetaCyc:MONOMER-8522; -.
DR   GO; GO:0005737; C:cytoplasm; EXP:UniProtKB.
DR   GO; GO:0008115; F:sarcosine oxidase activity; EXP:UniProtKB.
DR   GO; GO:0046653; P:tetrahydrofolate metabolic process; IEA:InterPro.
DR   Gene3D; 3.30.9.10; D-Amino Acid Oxidase, subunit A, domain 2; 1.
DR   Gene3D; 3.50.50.60; FAD/NAD(P)-binding domain; 1.
DR   InterPro; IPR006076; FAD-dep_OxRdtase.
DR   InterPro; IPR036188; FAD/NAD-bd_sf.
DR   InterPro; IPR001763; Rhodanese-like_dom.
DR   InterPro; IPR006278; SoxB.
DR   NCBIfam; TIGR01373; soxB; 1.
DR   PANTHER; PTHR13847:SF287; FAD-DEPENDENT OXIDOREDUCTASE DOMAIN-CONTAINING PROTEIN 1; 1.
DR   PANTHER; PTHR13847; SARCOSINE DEHYDROGENASE-RELATED; 1.
DR   Pfam; PF01266; DAO; 1.
DR   SUPFAM; SSF54373; FAD-linked reductases, C-terminal domain; 1.
DR   SUPFAM; SSF51905; FAD/NAD(P)-binding domain; 1.
PE   1: Evidence at protein level;
KW   Cytoplasm; Direct protein sequencing; FAD; Flavoprotein; FMN;
KW   Nucleotide-binding; Oxidoreductase.
FT   INIT_MET        1
FT                   /note="Removed"
FT                   /evidence="ECO:0000269|PubMed:7543100"
FT   CHAIN           2..405
FT                   /note="Sarcosine oxidase subunit beta"
FT                   /id="PRO_0000072044"
FT   BINDING         31
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         32
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         53
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         61
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         62
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         66
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         68
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         197
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         354
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         357
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   BINDING         359
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250|UniProtKB:Q50LF2"
FT   MOD_RES         173
FT                   /note="Tele-8alpha-FMN histidine"
FT                   /evidence="ECO:0000269|PubMed:11330998,
FT                   ECO:0000269|PubMed:9485355"
FT   MUTAGEN         30
FT                   /note="G->A: Prevents covalent attachment of FMN. Blocks
FT                   subunit assembly."
FT                   /evidence="ECO:0000269|PubMed:11330998"
FT   MUTAGEN         146
FT                   /note="C->S: No change in activity."
FT                   /evidence="ECO:0000269|PubMed:11330998"
FT   MUTAGEN         173
FT                   /note="H->N: Prevents covalent attachment of FMN. Loss of
FT                   activity. The mutant is considerably less stable than
FT                   wild-type enzyme, the beta and delta subunits are lost
FT                   during purification, which yields a stable alpha-gamma
FT                   complex."
FT                   /evidence="ECO:0000269|PubMed:11330998"
FT   MUTAGEN         175
FT                   /note="H->A: No effect on FMN binding and activity."
FT                   /evidence="ECO:0000269|PubMed:9485355"
FT   MUTAGEN         195
FT                   /note="C->S: No change in activity."
FT                   /evidence="ECO:0000269|PubMed:11330998"
FT   MUTAGEN         351
FT                   /note="C->A: No change in activity."
FT                   /evidence="ECO:0000269|PubMed:11330998"
SQ   SEQUENCE   405 AA;  43987 MW;  401141810BA60CDE CRC64;
     MADLLPEHPE FLWANPEPKK SYDVVIVGGG GHGLATAYYL AKNHGITNVA VLEKGWLAGG
     NMARNTTIIR SNYLWDESAG IYEKSLKLWE QLPEELDYDF LFSQRGVLNL AHTLGDVRES
     VRRVEANKFN GVDAEWLTPE QVKEVCPIIN IGDDIRYPVM GATYQPRAGI AKHDHVAWAF
     ARKANEMGVD IIQNCEVTGF LKDGEKVTGV KTTRGTIHAG KVALAGAGHS SVLAELAGFE
     LPIQSHPLQA LVSELFEPVH PTVVMSNHIH VYVSQAHKGE LVMGAGIDSY NGYGQRGAFH
     VIEEQMAAAV ELFPIFARAH VLRTWGGIVD TTMDASPIIS KTPIQNLYVN CGWGTGGFKG
     TPGAGFTLAH TIANDEAHAL NAPFSLERFE TGHLIDEHGA AAVAH
//