KTRB_VIBAL
ID KTRB_VIBAL Reviewed; 455 AA.
AC O87953;
DT 03-SEP-2014, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1998, sequence version 1.
DT 25-MAY-2022, entry version 48.
DE RecName: Full=Ktr system potassium uptake protein B;
DE Short=K(+)-uptake protein KtrB;
GN Name=ktrB;
OS Vibrio alginolyticus.
OC Bacteria; Proteobacteria; Gammaproteobacteria; Vibrionales; Vibrionaceae;
OC Vibrio.
OX NCBI_TaxID=663;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, AND GENE NAME.
RX PubMed=9642210; DOI=10.1128/jb.180.13.3491-3494.1998;
RA Nakamura T., Yuda R., Unemoto T., Bakker E.P.;
RT "KtrAB, a new type of bacterial K(+)-uptake system from Vibrio
RT alginolyticus.";
RL J. Bacteriol. 180:3491-3494(1998).
RN [2]
RP FUNCTION, ACTIVITY REGULATION, SUBCELLULAR LOCATION, DOMAIN, AND
RP MUTAGENESIS OF GLY-290.
RX PubMed=10359077; DOI=10.1016/s0014-5793(99)00504-9;
RA Tholema N., Bakker E.P., Suzuki A., Nakamura T.;
RT "Change to alanine of one out of four selectivity filter glycines in KtrB
RT causes a two orders of magnitude decrease in the affinities for both K+ and
RT Na+ of the Na+ dependent K+ uptake system KtrAB from Vibrio
RT alginolyticus.";
RL FEBS Lett. 450:217-220(1999).
RN [3]
RP FUNCTION, BIOPHYSICOCHEMICAL PROPERTIES, SUBUNIT, SUBCELLULAR LOCATION,
RP DOMAIN, AND MUTAGENESIS OF GLY-70; GLY-185; GLY-290 AND GLY-402.
RX PubMed=16210320; DOI=10.1074/jbc.m507647200;
RA Tholema N., Vor der Brueggen M., Maeser P., Nakamura T., Schroeder J.I.,
RA Kobayashi H., Uozumi N., Bakker E.P.;
RT "All four putative selectivity filter glycine residues in KtrB are
RT essential for high affinity and selective K+ uptake by the KtrAB system
RT from Vibrio alginolyticus.";
RL J. Biol. Chem. 280:41146-41154(2005).
RN [4]
RP SUBUNIT.
RX PubMed=17344221; DOI=10.1074/jbc.m609084200;
RA Kroening N., Willenborg M., Tholema N., Haenelt I., Schmid R., Bakker E.P.;
RT "ATP binding to the KTN/RCK subunit KtrA from the K+ -uptake system KtrAB
RT of Vibrio alginolyticus: its role in the formation of the KtrAB complex and
RT its requirement in vivo.";
RL J. Biol. Chem. 282:14018-14027(2007).
RN [5]
RP SUBUNIT, SUBCELLULAR LOCATION, AND MUTAGENESIS OF GLY-314; GLY-316;
RP SER-317; THR-318; THR-320; GLY-321; GLY-322; GLY-323; ILE-324; LYS-325;
RP VAL-326; SER-327 AND 326-VAL--THR-328.
RX PubMed=20097755; DOI=10.1074/jbc.m109.089870;
RA Haenelt I., Loechte S., Sundermann L., Elbers K., Vor der Brueggen M.,
RA Bakker E.P.;
RT "Gain of function mutations in membrane region M2C2 of KtrB open a gate
RT controlling K+ transport by the KtrAB system from Vibrio alginolyticus.";
RL J. Biol. Chem. 285:10318-10327(2010).
CC -!- FUNCTION: Part of the Na(+)-dependent high affinity K(+) uptake system
CC KtrAB. KtrB is the K(+)-translocating subunit.
CC {ECO:0000269|PubMed:10359077, ECO:0000269|PubMed:16210320,
CC ECO:0000269|PubMed:9642210}.
CC -!- ACTIVITY REGULATION: K(+) transport is stimulated by Na(+).
CC {ECO:0000269|PubMed:10359077}.
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=0.025 mM for K(+) {ECO:0000269|PubMed:16210320};
CC KM=6 mM for Na(+) {ECO:0000269|PubMed:16210320};
CC Vmax=200 nmol/min/mg enzyme with K(+) as substrate
CC {ECO:0000269|PubMed:16210320};
CC Vmax=110 nmol/min/mg enzyme with Na(+) as substrate
CC {ECO:0000269|PubMed:16210320};
CC -!- SUBUNIT: The uptake system is composed of KtrA and KtrB.
CC {ECO:0000269|PubMed:16210320, ECO:0000269|PubMed:17344221,
CC ECO:0000269|PubMed:20097755}.
CC -!- SUBCELLULAR LOCATION: Cell inner membrane {ECO:0000269|PubMed:10359077,
CC ECO:0000269|PubMed:16210320, ECO:0000269|PubMed:20097755}; Multi-pass
CC membrane protein {ECO:0000269|PubMed:10359077,
CC ECO:0000269|PubMed:16210320, ECO:0000269|PubMed:20097755}.
CC -!- DOMAIN: Contains four repeated domains, each composed of two
CC transmembrane helices connected by a putative pore loop (p-loop). Four
CC conserved glycine residues in the p-loops are part of a selectivity
CC filter for K(+) ions. {ECO:0000269|PubMed:10359077,
CC ECO:0000269|PubMed:16210320}.
CC -!- MISCELLANEOUS: KtrB alone mediates slow Na(+)-independent K(+) uptake,
CC as well as K(+)-independent Na(+) uptake.
CC {ECO:0000305|PubMed:20097755}.
CC -!- SIMILARITY: Belongs to the TrkH potassium transport family. Ktr (TC
CC 2.A.38.4) subfamily. {ECO:0000305}.
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DR EMBL; D89592; BAA32063.1; -; Genomic_DNA.
DR AlphaFoldDB; O87953; -.
DR SMR; O87953; -.
DR TCDB; 2.A.38.4.2; the k(+) transporter (trk) family.
DR eggNOG; COG0168; Bacteria.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0015379; F:potassium:chloride symporter activity; IEA:InterPro.
DR InterPro; IPR003445; Cat_transpt.
DR InterPro; IPR004772; TrkH.
DR Pfam; PF02386; TrkH; 1.
DR TIGRFAMs; TIGR00933; 2a38; 1.
PE 1: Evidence at protein level;
KW Cell inner membrane; Cell membrane; Ion transport; Membrane; Potassium;
KW Potassium transport; Transmembrane; Transmembrane helix; Transport.
FT CHAIN 1..455
FT /note="Ktr system potassium uptake protein B"
FT /id="PRO_0000430033"
FT TRANSMEM 27..47
FT /note="Helical"
FT /evidence="ECO:0000255"
FT INTRAMEM 54..74
FT /evidence="ECO:0000255"
FT TRANSMEM 86..106
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 141..161
FT /note="Helical"
FT /evidence="ECO:0000255"
FT INTRAMEM 169..189
FT /evidence="ECO:0000255"
FT TRANSMEM 201..221
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 240..260
FT /note="Helical"
FT /evidence="ECO:0000255"
FT INTRAMEM 291..313
FT /evidence="ECO:0000255"
FT TRANSMEM 318..340
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 362..382
FT /note="Helical"
FT /evidence="ECO:0000255"
FT INTRAMEM 390..410
FT /evidence="ECO:0000255"
FT TRANSMEM 418..438
FT /note="Helical"
FT /evidence="ECO:0000255"
FT MUTAGEN 70
FT /note="G->A,S: Decrease in K(+) uptake activity."
FT /evidence="ECO:0000269|PubMed:16210320"
FT MUTAGEN 70
FT /note="G->D: Exhibits very low K(+) uptake activity."
FT /evidence="ECO:0000269|PubMed:16210320"
FT MUTAGEN 185
FT /note="G->A,D: Decrease in K(+) uptake activity."
FT /evidence="ECO:0000269|PubMed:16210320"
FT MUTAGEN 185
FT /note="G->S: Exhibits very low K(+) uptake activity."
FT /evidence="ECO:0000269|PubMed:16210320"
FT MUTAGEN 290
FT /note="G->A: Decrease in K(+) uptake activity."
FT /evidence="ECO:0000269|PubMed:10359077,
FT ECO:0000269|PubMed:16210320"
FT MUTAGEN 290
FT /note="G->D,S: Lack of K(+) uptake activity."
FT /evidence="ECO:0000269|PubMed:10359077,
FT ECO:0000269|PubMed:16210320"
FT MUTAGEN 314
FT /note="G->A: Does not affect Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 316
FT /note="G->A,S: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 317
FT /note="S->C: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 318
FT /note="T->C: Does not affect Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 320
FT /note="T->C: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 321
FT /note="G->A,S: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 322
FT /note="G->C: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 323
FT /note="G->S: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 324
FT /note="I->C: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 325
FT /note="K->C,D,H,Q,R: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 326..328
FT /note="Missing: Abolishes binding to KtrA. Transports Na(+)
FT faster."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 326
FT /note="V->C,S,T: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 327
FT /note="S->C: Increases Vmax for K(+) transport."
FT /evidence="ECO:0000269|PubMed:20097755"
FT MUTAGEN 402
FT /note="G->A,D,S: Exhibits very low K(+) uptake activity."
FT /evidence="ECO:0000269|PubMed:16210320"
SQ SEQUENCE 455 AA; 49664 MW; 3E93A4F5FC73B2C2 CRC64;
MTQFHQRGVF YVPDGKRDKA KGGEPRIILL SFLGVLLPSA VLLTLPVFSV SGLSITDALF
TATSAISVTG LGVVDTGQHF TLAGKILLMC LMQIGGLGQM TLSAVLLYMF GVRLSLRQQA
LAKEALGQER QVNLRRLVKK IVTFALVAEA IGFVFLSYRW VPEMGWQTGM FYALFHSISA
FNNAGFALFS DSMMSFVNDP LVSFTLAGLF IFGGLGFTVI GDVWRHWRKG FHFLHIHTKI
MLIATPLLLL VGTVLFWLLE RHNPNTMGSL TTGGQWLAAF FQSASARTAG FNSVDLTQFT
QPALLIMIVL MLIGAGSTST GGGIKVSTFA VAFMATWTFL RQKKHVVMFK RTVNWPTVTK
SLAIIVVSGA ILTTAMFLLM LTEKASFDKV MFETISAFAT VGLTAGLTAE LSEPGKYIMI
VVMIIGRIGP LTLAYMLARP EPTLIKYPED TVLTG
