LOX_NOSS1
ID LOX_NOSS1 Reviewed; 365 AA.
AC Q8Z0C8; D4P2J5;
DT 23-FEB-2022, integrated into UniProtKB/Swiss-Prot.
DT 01-MAR-2002, sequence version 1.
DT 03-AUG-2022, entry version 109.
DE RecName: Full=L-lactate oxidase {ECO:0000303|PubMed:21828292};
DE Short=LOX {ECO:0000303|PubMed:21828292};
DE EC=1.1.3.- {ECO:0000269|PubMed:21828292};
DE AltName: Full=Glyoxylate oxidase {ECO:0000305|PubMed:21828292};
DE EC=1.2.3.5 {ECO:0000269|PubMed:21828292};
DE AltName: Full=No-LOX {ECO:0000303|PubMed:21828292};
GN Name=lox {ECO:0000303|PubMed:21828292};
GN OrderedLocusNames=all0170 {ECO:0000312|EMBL:BAB77694.1};
OS Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576).
OC Bacteria; Cyanobacteria; Nostocales; Nostocaceae; Nostoc.
OX NCBI_TaxID=103690;
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=PCC 7120 / SAG 25.82 / UTEX 2576;
RX PubMed=11759840; DOI=10.1093/dnares/8.5.205;
RA Kaneko T., Nakamura Y., Wolk C.P., Kuritz T., Sasamoto S., Watanabe A.,
RA Iriguchi M., Ishikawa A., Kawashima K., Kimura T., Kishida Y., Kohara M.,
RA Matsumoto M., Matsuno A., Muraki A., Nakazaki N., Shimpo S., Sugimoto M.,
RA Takazawa M., Yamada M., Yasuda M., Tabata S.;
RT "Complete genomic sequence of the filamentous nitrogen-fixing
RT cyanobacterium Anabaena sp. strain PCC 7120.";
RL DNA Res. 8:205-213(2001).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 82-171, AND INDUCTION.
RC STRAIN=PCC 7120 / SAG 25.82 / UTEX 2576;
RX PubMed=21163840; DOI=10.1099/mic.0.045682-0;
RA Srivastava A.K., Alexova R., Jeon Y.J., Kohli G.S., Neilan B.A.;
RT "Assessment of salinity-induced photorespiratory glycolate metabolism in
RT Anabaena sp. PCC 7120.";
RL Microbiology 157:911-917(2011).
RN [3]
RP FUNCTION, CATALYTIC ACTIVITY, SUBSTRATE SPECIFICITY, BIOPHYSICOCHEMICAL
RP PROPERTIES, MUTAGENESIS OF MET-82; LEU-112 AND PHE-212, AND DISRUPTION
RP PHENOTYPE.
RC STRAIN=PCC 7120 / SAG 25.82 / UTEX 2576;
RX PubMed=21828292; DOI=10.1105/tpc.111.088070;
RA Hackenberg C., Kern R., Huge J., Stal L.J., Tsuji Y., Kopka J.,
RA Shiraiwa Y., Bauwe H., Hagemann M.;
RT "Cyanobacterial lactate oxidases serve as essential partners in N2 fixation
RT and evolved into photorespiratory glycolate oxidases in plants.";
RL Plant Cell 23:2978-2990(2011).
CC -!- FUNCTION: Catalyzes the oxidation of (S)-lactate (L-lactate) to
CC pyruvate, with a reduction of O2 to H2O2. In extant N2-fixing
CC cyanobacteria such as Nostoc, this enzyme primarily serves as an O2-
CC scavenging enzyme, protecting nitrogenase that is extremely sensitive
CC to O2, and is therefore an essential partner in N2 fixation. Also shows
CC clear oxidase activity with glyoxylate in vitro, and low activity with
CC glycerate, hydroxypyruvate and glycolate. The very low glycolate
CC oxidase activity indicates that this enzyme is unlikely to be involved
CC in photorespiratory glycolate metabolism, a pathway that seems to exist
CC in this cyanobacterium, but in which the oxidation of glycolate is
CC taken over by glycolate dehydrogenase (GlcD). Is not able to use D-
CC lactate as substrate and does not show any dehydrogenase activity with
CC NAD(+) or NADP(+). {ECO:0000269|PubMed:21828292}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(S)-lactate + O2 = H2O2 + pyruvate; Xref=Rhea:RHEA:55868,
CC ChEBI:CHEBI:15361, ChEBI:CHEBI:15379, ChEBI:CHEBI:16240,
CC ChEBI:CHEBI:16651; Evidence={ECO:0000269|PubMed:21828292};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:55869;
CC Evidence={ECO:0000269|PubMed:21828292};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=glyoxylate + H2O + O2 = H(+) + H2O2 + oxalate;
CC Xref=Rhea:RHEA:14837, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:15379, ChEBI:CHEBI:16240, ChEBI:CHEBI:30623,
CC ChEBI:CHEBI:36655; EC=1.2.3.5;
CC Evidence={ECO:0000269|PubMed:21828292};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:14838;
CC Evidence={ECO:0000269|PubMed:21828292};
CC -!- COFACTOR:
CC Name=FMN; Xref=ChEBI:CHEBI:58210;
CC Evidence={ECO:0000250|UniProtKB:Q44467};
CC Note=Binds 1 FMN per subunit. {ECO:0000250|UniProtKB:Q44467};
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=0.039 mM for (S)-lactate {ECO:0000269|PubMed:21828292};
CC KM=0.233 mM for glycolate {ECO:0000269|PubMed:21828292};
CC Vmax=12.73 umol/min/mg enzyme with (S)-lactate as substrate
CC {ECO:0000269|PubMed:21828292};
CC Vmax=0.049 umol/min/mg enzyme with glycolate as substrate
CC {ECO:0000269|PubMed:21828292};
CC -!- SUBUNIT: Homotetramer. {ECO:0000250|UniProtKB:Q44467}.
CC -!- INDUCTION: Up-regulated by high salinity conditions (NaCl exposure).
CC {ECO:0000269|PubMed:21163840}.
CC -!- DISRUPTION PHENOTYPE: Deletion of this gene does not affect growth in
CC nitrate-containing medium under normal photorespiratory conditions.
CC However, the mutant is unable to grow diazotrophically, caused by its
CC inability to protect nitrogenase from O2 inhibition.
CC {ECO:0000269|PubMed:21828292}.
CC -!- SIMILARITY: Belongs to the FMN-dependent alpha-hydroxy acid
CC dehydrogenase family. {ECO:0000305}.
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DR EMBL; BA000019; BAB77694.1; -; Genomic_DNA.
DR EMBL; GU560732; ADD64504.1; -; Genomic_DNA.
DR PIR; AB1828; AB1828.
DR RefSeq; WP_010994347.1; NZ_RSCN01000026.1.
DR STRING; 103690.17135148; -.
DR EnsemblBacteria; BAB77694; BAB77694; BAB77694.
DR KEGG; ana:all0170; -.
DR eggNOG; COG1304; Bacteria.
DR OMA; FTRLMQT; -.
DR OrthoDB; 1186741at2; -.
DR BRENDA; 1.1.3.2; 8113.
DR Proteomes; UP000002483; Chromosome.
DR GO; GO:0010181; F:FMN binding; IEA:InterPro.
DR GO; GO:0016491; F:oxidoreductase activity; IEA:UniProtKB-KW.
DR CDD; cd02809; alpha_hydroxyacid_oxid_FMN; 1.
DR Gene3D; 3.20.20.70; -; 1.
DR InterPro; IPR013785; Aldolase_TIM.
DR InterPro; IPR012133; Alpha-hydoxy_acid_DH_FMN.
DR InterPro; IPR000262; FMN-dep_DH.
DR InterPro; IPR037396; FMN_HAD.
DR InterPro; IPR008259; FMN_hydac_DH_AS.
DR Pfam; PF01070; FMN_dh; 1.
DR PIRSF; PIRSF000138; Al-hdrx_acd_dh; 1.
DR PROSITE; PS00557; FMN_HYDROXY_ACID_DH_1; 1.
DR PROSITE; PS51349; FMN_HYDROXY_ACID_DH_2; 1.
PE 1: Evidence at protein level;
KW Flavoprotein; FMN; Oxidoreductase; Reference proteome.
FT CHAIN 1..365
FT /note="L-lactate oxidase"
FT /id="PRO_0000454868"
FT DOMAIN 2..365
FT /note="FMN hydroxy acid dehydrogenase"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00683"
FT ACT_SITE 263
FT /note="Proton acceptor"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 28
FT /ligand="pyruvate"
FT /ligand_id="ChEBI:CHEBI:15361"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 81..83
FT /ligand="FMN"
FT /ligand_id="ChEBI:CHEBI:58210"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 110
FT /ligand="FMN"
FT /ligand_id="ChEBI:CHEBI:58210"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 135
FT /ligand="FMN"
FT /ligand_id="ChEBI:CHEBI:58210"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 137
FT /ligand="pyruvate"
FT /ligand_id="ChEBI:CHEBI:15361"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 163
FT /ligand="FMN"
FT /ligand_id="ChEBI:CHEBI:58210"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 172
FT /ligand="pyruvate"
FT /ligand_id="ChEBI:CHEBI:15361"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 239
FT /ligand="FMN"
FT /ligand_id="ChEBI:CHEBI:58210"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 261
FT /ligand="FMN"
FT /ligand_id="ChEBI:CHEBI:58210"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 263
FT /ligand="pyruvate"
FT /ligand_id="ChEBI:CHEBI:15361"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 266
FT /ligand="pyruvate"
FT /ligand_id="ChEBI:CHEBI:15361"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 294..298
FT /ligand="FMN"
FT /ligand_id="ChEBI:CHEBI:58210"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT BINDING 318
FT /ligand="FMN"
FT /ligand_id="ChEBI:CHEBI:58210"
FT /evidence="ECO:0000250|UniProtKB:Q44467"
FT MUTAGEN 82
FT /note="M->T: Increases oxidation activity with both L-
FT lactate and glycolate. Shows a 6-fold decrease in the L-
FT lactate/glycolate oxidase activity ratio."
FT /evidence="ECO:0000269|PubMed:21828292"
FT MUTAGEN 112
FT /note="L->W: Impairs oxidation of L-lactate. Shows a 2-fold
FT decrease in the L-lactate/glycolate oxidase activity
FT ratio."
FT /evidence="ECO:0000269|PubMed:21828292"
FT MUTAGEN 212
FT /note="F->V: Impairs oxidation of L-lactate. Shows a 27-
FT fold decrease in the L-lactate/glycolate oxidase activity
FT ratio."
FT /evidence="ECO:0000269|PubMed:21828292"
SQ SEQUENCE 365 AA; 39165 MW; D31BCE31565E6622 CRC64;
MTAISSPINL FEYEQLAKTH LSQMAFDYYI SGAGDEITLQ ENRAVFERIK LRPRMLVDVS
QINLTTSVLG QPLQLPLLIA PMAFQCLAHT EGELATAMAA ASAGTGMVLS TLSTKSLEEV
AEVGSKFSPS LQWFQLYIHK DRGLTRALVE RAYAAGYKAL CLTVDAPVLG QRERDRRNEF
VLPPGLHLAN LTTISGLNIP HAPGESGLFT YFAQQLNPAL TWDDLEWLQS LSPLPLVLKG
ILRGDDAARA VEYGAKAIVV SNHGGRQLDG AIASLDALPE IVAAVNGKAE VLLDGGIRRG
TDIIKALAIG AQAVLIGRPV LWGLAVGGQA GVSHVISLLQ KELNVAMALI GCSQLQDIDT
SFLHL
