ID   ALBA_STRNR              Reviewed;         219 AA.
AC   Q8GED9;
DT   18-SEP-2013, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2003, sequence version 1.
DT   25-MAY-2022, entry version 48.
DE   RecName: Full=Albonoursin synthase;
DE            EC=1.3.3.13;
DE   AltName: Full=Albonoursin synthase protein A;
DE   AltName: Full=Cyclic dipeptide oxidase;
DE            Short=CDO;
GN   Name=albA;
OS   Streptomyces noursei.
OC   Bacteria; Actinobacteria; Streptomycetales; Streptomycetaceae;
OC   Streptomyces.
OX   NCBI_TaxID=1971;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, AND NOMENCLATURE.
RC   STRAIN=ATCC 11455 / DSM 40635 / JCM 4922 / NBRC 15452 / NCIMB 8593 / NRRL
RC   B-1714;
RX   PubMed=12498889; DOI=10.1016/s1074-5521(02)00285-5;
RA   Lautru S., Gondry M., Genet R., Pernodet J.L.;
RT   "The albonoursin gene cluster of S noursei biosynthesis of diketopiperazine
RT   metabolites independent of nonribosomal peptide synthetases.";
RL   Chem. Biol. 9:1355-1364(2002).
RN   [2]
RP   FUNCTION, CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES, BLOCKAGE OF
RP   N-TERMINUS, SUBCELLULAR LOCATION, COFACTOR, AND SUBSTRATE SPECIFICITY.
RC   STRAIN=ATCC 11455 / DSM 40635 / JCM 4922 / NBRC 15452 / NCIMB 8593 / NRRL
RC   B-1714;
RX   PubMed=11248691; DOI=10.1046/j.1432-1033.2001.02038.x;
RA   Gondry M., Lautru S., Fusai G., Meunier G., Menez A., Genet R.;
RT   "Cyclic dipeptide oxidase from Streptomyces noursei. Isolation,
RT   purification and partial characterization of a novel, amino acyl
RT   alpha,beta-dehydrogenase.";
RL   Eur. J. Biochem. 268:1712-1721(2001).
CC   -!- FUNCTION: Involved in the biosynthesis of albonoursin
CC       (cyclo[(alpha,beta-dehydro-Phe)-(alpha,beta-dehydro-Leu)]), an
CC       antibacterial peptide. Catalyzes the formation of alpha,beta-dehydro-
CC       Phe (DPhe) and alpha,beta-dehydro-Leu (DLeu) residues during the
CC       biosynthesis of albonoursin. The catalytic reaction of cyclo(L-Phe-L-
CC       Leu) occurs in a two-step sequential alpha-beta-dehydrogenation leading
CC       first to cyclo(alpha,beta-dehydro-Phe-L-Leu) and finally to
CC       albonoursin. Can also use cyclo(L-Phe-L-His), cyclo(L-Trp-L-Trp),
CC       cyclo(L-Leu-L-Ala), cyclo(L-Phe-Gly), cyclo(L-Leu-Gly), cyclo(L-Ser-
CC       Gly) and cyclo(L-Glu-Gly) as substrate suggesting that the
CC       diketopiperazine ring is essential for the enzymatic reaction.
CC       {ECO:0000269|PubMed:11248691, ECO:0000269|PubMed:12498889}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=cyclo(L-phenylalanyl-L-leucyl) + 2 O2 = albonoursin + 2 H2O2;
CC         Xref=Rhea:RHEA:35531, ChEBI:CHEBI:15379, ChEBI:CHEBI:16240,
CC         ChEBI:CHEBI:71608, ChEBI:CHEBI:71609; EC=1.3.3.13;
CC         Evidence={ECO:0000269|PubMed:11248691};
CC   -!- COFACTOR:
CC       Name=FMN; Xref=ChEBI:CHEBI:58210;
CC         Evidence={ECO:0000305|PubMed:11248691};
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         KM=53 uM for cyclo(L-Phe-L-Leu) (at pH 8 and 30 degrees Celsius)
CC         {ECO:0000269|PubMed:11248691};
CC         KM=67 uM for cyclo(L-Phe-L-His) (at pH 8 and 30 degrees Celsius)
CC         {ECO:0000269|PubMed:11248691};
CC         Note=kcat is 0.453 and 0.69 sec(-1) for cyclo(L-Phe-L-His) and
CC         cyclo(L-Phe-L-Leu), respectively.;
CC       pH dependence:
CC         Optimum pH is 8. {ECO:0000269|PubMed:11248691};
CC       Temperature dependence:
CC         Optimum temperature is 60 degrees Celsius. The activity increases
CC         quite linearly with temperature and is nearly twice as high at 60
CC         degrees Celsius as compared to 30 degrees Celsius. Above 60 degrees
CC         Celsius, the enzyme activity dramatically decreases, probably due to
CC         thermal inactivation. {ECO:0000269|PubMed:11248691};
CC   -!- SUBUNIT: Homomer.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000305|PubMed:11248691}.
CC   -!- PTM: The N-terminus is blocked.
CC   -!- SIMILARITY: Belongs to the nitroreductase family. {ECO:0000305}.
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DR   EMBL; AY129235; AAN07907.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q8GED9; -.
DR   SMR; Q8GED9; -.
DR   KEGG; ag:AAN07907; -.
DR   BRENDA; 1.3.3.13; 11755.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0016634; F:oxidoreductase activity, acting on the CH-CH group of donors, oxygen as acceptor; IDA:UniProtKB.
DR   Gene3D; 3.40.109.10; -; 1.
DR   InterPro; IPR029479; Nitroreductase.
DR   InterPro; IPR000415; Nitroreductase-like.
DR   Pfam; PF00881; Nitroreductase; 2.
DR   SUPFAM; SSF55469; SSF55469; 1.
PE   1: Evidence at protein level;
KW   Cytoplasm; Flavoprotein; FMN; Oxidoreductase.
FT   CHAIN           1..219
FT                   /note="Albonoursin synthase"
FT                   /id="PRO_0000423357"
SQ   SEQUENCE   219 AA;  23763 MW;  3C4875C10C4082A3 CRC64;
     MRRHPSHSPY RGGCEVRPKR RGLMLAHSSS ESPPESLPDA WTVLKTRTAV RNYAKEPVDD
     ALIEQLLEAM LAAPTASNRQ AWSFMVVRRP AAVRRLRAFS PGVLGTPAFF VVACVDRSLT
     DNLSPKLSQK IYDTSKLCVA MAVENLLLAA HAAGLGGCPV GSFRSDIVTS MLGIPEHIEP
     MLVVPIGRPA TALVPSQRRA KNEVVNYESW GNRAAAPTA