ID   NFR2_LACJO              Reviewed;         184 AA.
AC   Q74HL8;
DT   09-JUL-2014, integrated into UniProtKB/Swiss-Prot.
DT   05-JUL-2004, sequence version 1.
DT   25-MAY-2022, entry version 96.
DE   RecName: Full=NADH-dependent flavin reductase subunit 2;
DE            EC=1.5.1.36;
GN   Name=nfr2; OrderedLocusNames=LJ_0549;
OS   Lactobacillus johnsonii (strain CNCM I-12250 / La1 / NCC 533).
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae;
OC   Lactobacillus.
OX   NCBI_TaxID=257314;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=CNCM I-1225 / La1 / NCC 533;
RX   PubMed=14983040; DOI=10.1073/pnas.0307327101;
RA   Pridmore R.D., Berger B., Desiere F., Vilanova D., Barretto C.,
RA   Pittet A.-C., Zwahlen M.-C., Rouvet M., Altermann E., Barrangou R.,
RA   Mollet B., Mercenier A., Klaenhammer T., Arigoni F., Schell M.A.;
RT   "The genome sequence of the probiotic intestinal bacterium Lactobacillus
RT   johnsonii NCC 533.";
RL   Proc. Natl. Acad. Sci. U.S.A. 101:2512-2517(2004).
RN   [2]
RP   IDENTIFICATION BY MASS SPECTROMETRY, FUNCTION, ROLE IN H(2)O(2) PRODUCTION,
RP   SUBUNIT, AND DISRUPTION PHENOTYPE.
RC   STRAIN=CNCM I-1225 / La1 / NCC 533;
RX   PubMed=24487531; DOI=10.1128/aem.04272-13;
RA   Hertzberger R., Arents J., Dekker H.L., Pridmore R.D., Gysler C.,
RA   Kleerebezem M., de Mattos M.J.;
RT   "H(2)O(2) production in species of the Lactobacillus acidophilus group: a
RT   central role for a novel NADH-dependent flavin reductase.";
RL   Appl. Environ. Microbiol. 80:2229-2239(2014).
CC   -!- FUNCTION: Component of an enzyme that catalyzes the reduction of free
CC       flavins (FMN, FAD and riboflavin) by NADH; the reduced flavins produced
CC       by this reaction likely spontaneously react with oxygen, yielding
CC       hydrogen peroxide. Is responsible for the major H(2)O(2) production in
CC       L.johnsonii in the presence of oxygen. Cannot use NADPH instead of NADH
CC       as the electron donor. {ECO:0000269|PubMed:24487531}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a reduced flavin + NAD(+) = an oxidized flavin + 2 H(+) +
CC         NADH; Xref=Rhea:RHEA:31303, ChEBI:CHEBI:15378, ChEBI:CHEBI:57540,
CC         ChEBI:CHEBI:57945, ChEBI:CHEBI:60531, ChEBI:CHEBI:62787; EC=1.5.1.36;
CC   -!- SUBUNIT: Requires LJ_0548 for activity, but the exact composition of
CC       the enzyme is unclear. {ECO:0000269|PubMed:24487531}.
CC   -!- DISRUPTION PHENOTYPE: Cells lacking both LJ_0548 and LJ_0549 completely
CC       lack the NADH-dependent flavin reductase activity detected in wild-type
CC       strain, and show a 40-fold reduction of hydrogen peroxide formation
CC       upon exposure to oxygen. Reductase activity and H(2)O(2) production in
CC       this mutant can only be restored by in trans complementation of both
CC       genes. {ECO:0000269|PubMed:24487531}.
CC   -!- SIMILARITY: Belongs to the NADH-dependent flavin reductase family.
CC       {ECO:0000305}.
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DR   EMBL; AE017198; AAS09672.1; -; Genomic_DNA.
DR   RefSeq; WP_004898036.1; NC_005362.1.
DR   AlphaFoldDB; Q74HL8; -.
DR   SMR; Q74HL8; -.
DR   STRING; 257314.LJ_0549; -.
DR   EnsemblBacteria; AAS09672; AAS09672; LJ_0549.
DR   GeneID; 66436135; -.
DR   KEGG; ljo:LJ_0549; -.
DR   eggNOG; COG0431; Bacteria.
DR   HOGENOM; CLU_055322_4_0_9; -.
DR   OMA; LKSAMEW; -.
DR   BRENDA; 1.5.1.36; 2846.
DR   Proteomes; UP000000581; Chromosome.
DR   GO; GO:0036382; F:flavin reductase (NADH) activity; IEA:UniProtKB-EC.
DR   Gene3D; 3.40.50.360; -; 1.
DR   InterPro; IPR029039; Flavoprotein-like_sf.
DR   InterPro; IPR005025; FMN_Rdtase-like.
DR   Pfam; PF03358; FMN_red; 1.
DR   SUPFAM; SSF52218; SSF52218; 1.
PE   1: Evidence at protein level;
KW   Flavoprotein; FMN; NAD; Oxidoreductase; Reference proteome.
FT   CHAIN           1..184
FT                   /note="NADH-dependent flavin reductase subunit 2"
FT                   /id="PRO_0000429767"
SQ   SEQUENCE   184 AA;  20572 MW;  AF6A11BDE164A4CF CRC64;
     MKLLAIVGTN ADFSYNRFLD QFMAKRYKDQ AEIEVYEIAD LPRFKKEAQP DSKVEEFKNK
     IREADGVIFA TPEYDHGIPS ALKSAMEWTG SHAQGNADVM KMKPAMVLGT SYGIQGASRA
     QEEMREILLS PDQSANVLPG NEVLIGHAAD KFDKNTGDLL DQETIHAIDL AFNNFVKFVE
     QAQK