ID   NIAX_LACLM              Reviewed;         222 AA.
AC   A2RKV5;
DT   31-MAY-2011, integrated into UniProtKB/Swiss-Prot.
DT   06-MAR-2007, sequence version 1.
DT   25-MAY-2022, entry version 57.
DE   RecName: Full=Niacin transporter NiaX;
DE   AltName: Full=Niacin ECF transporter S component NiaX;
GN   Name=niaX; OrderedLocusNames=llmg_1330;
OS   Lactococcus lactis subsp. cremoris (strain MG1363).
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Streptococcaceae;
OC   Lactococcus; Lactococcus cremoris subsp. cremoris.
OX   NCBI_TaxID=416870;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=MG1363;
RX   PubMed=17307855; DOI=10.1128/jb.01768-06;
RA   Wegmann U., O'Connell-Motherway M., Zomer A., Buist G., Shearman C.,
RA   Canchaya C., Ventura M., Goesmann A., Gasson M.J., Kuipers O.P.,
RA   van Sinderen D., Kok J.;
RT   "The complete genome sequence of the lactic acid bacterial paradigm
RT   Lactococcus lactis subsp. cremoris MG1363.";
RL   J. Bacteriol. 189:3256-3270(2007).
RN   [2]
RP   IDENTIFICATION BY MASS SPECTROMETRY, FUNCTION IN TRANSPORT, SUBUNIT,
RP   SUBCELLULAR LOCATION, AND EXPRESSION IN E.COLI AND L.LACTIS.
RC   STRAIN=MG1363;
RX   PubMed=21135102; DOI=10.1074/jbc.m110.199224;
RA   ter Beek J., Duurkens R.H., Erkens G.B., Slotboom D.J.;
RT   "Quaternary structure and functional unit of energy coupling factor (ECF)-
RT   type transporters.";
RL   J. Biol. Chem. 286:5471-5475(2011).
CC   -!- FUNCTION: Probably a niacin-binding protein that interacts with the
CC       energy-coupling factor (ECF) ABC-transporter complex. Unlike classic
CC       ABC transporters this ECF transporter provides the energy necessary to
CC       transport a number of different substrates. The substrates themselves
CC       are bound by transmembrane, not extracytoplasmic soluble proteins.
CC       Uptake of niacin into proteosomes containing EcfA1A2T and Niax has been
CC       demonstrated. Uptake requires hydrolyzable Mg-ATP and is substrate-
CC       specific; NiaX-containing proteosomes did not transport riboflavin.
CC       {ECO:0000269|PubMed:21135102}.
CC   -!- SUBUNIT: In L.lactis forms a stable complex with EcfA, EcfA' and EcfT.
CC       In E.coli forms a stable energy-coupling factor (ECF) transporter
CC       complex composed of 2 membrane-embedded substrate-binding proteins (S
CC       component), 2 ATP-binding proteins (A and A' components) and 2
CC       transmembrane proteins (T component), probably with a stoichiometry of
CC       2:1:1:2. May be able to interact with more than 1 S component at a
CC       time. {ECO:0000269|PubMed:21135102}.
CC   -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000305|PubMed:21135102};
CC       Multi-pass membrane protein {ECO:0000305|PubMed:21135102}.
CC   -!- SIMILARITY: Belongs to the vitamin uptake transporter (VUT/ECF) (TC
CC       2.A.88) family. {ECO:0000305}.
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DR   EMBL; AM406671; CAL97921.1; -; Genomic_DNA.
DR   AlphaFoldDB; A2RKV5; -.
DR   SMR; A2RKV5; -.
DR   STRING; 416870.llmg_1330; -.
DR   TCDB; 2.A.88.5.2; the vitamin uptake transporter (vut) family.
DR   EnsemblBacteria; CAL97921; CAL97921; llmg_1330.
DR   KEGG; llm:llmg_1330; -.
DR   eggNOG; ENOG50311D4; Bacteria.
DR   HOGENOM; CLU_118978_0_0_9; -.
DR   OMA; SHIIFGC; -.
DR   PhylomeDB; A2RKV5; -.
DR   Proteomes; UP000000364; Chromosome.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0005886; C:plasma membrane; IDA:UniProtKB.
DR   GO; GO:0042626; F:ATPase-coupled transmembrane transporter activity; IDA:GO_Central.
PE   1: Evidence at protein level;
KW   Cell membrane; Membrane; Transmembrane; Transmembrane helix; Transport.
FT   CHAIN           1..222
FT                   /note="Niacin transporter NiaX"
FT                   /id="PRO_0000409011"
FT   TRANSMEM        34..54
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        72..94
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        101..120
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        135..155
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        167..187
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   222 AA;  24640 MW;  C2DD7E6E61547724 CRC64;
     MRNHDCPTVR FFKARVYKEK ETQMTQTKKA KVRNLIIAAM LTALGILIPM MMPVKLIIGP
     ASFTLAAHVP VMAAMFFSPL MTAFVALGTT LGFMISIPVP TIWLRALMHL PVMTVGAYVL
     KKYPEFVHQK VKIQIFNFIL GIFHAGLETL VVYAFYSLGF ANIEQGALLN FLLLIALGGL
     VHSMIDFNLA LGLGNVLSKA FPIDIFDKAK NLVNKKKVKA EI