ktrB

high affinity potassium channel KtrA-KtrB, integral membrane subunit

Locus: BSU_31100

Isoelectric point: 10.12

Molecular weight: 48.27 kDa

Protein length: 445 aa

Gene length: 1338 bp

Function: potassium uptake

Product: high affinity potassium channel KtrA-KtrB, integral membrane subunit

Essential: no

Synonyms: yubG

Genomic Context

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Categories containing this gene/protein

• Cellular processes → Transporters → Transporters/ other → Metal ion transporter
• Cellular processes → Homeostasis → Metal ion homeostasis (K, Na, Ca, Mg) → Potassium uptake/ export
• Lifestyles → Coping with stress → Coping with hyper-osmotic stress
• Groups of genes → Membrane proteins

Gene

Coordinates: 3,189,089 3,190,426

Phenotypes of a mutant

• a kimA ktrA ktrB mutant requires high potassium concentrations on minimal medium with ammonium as nitrogen source PubMed

The protein

Catalyzed reaction/ biological activity

• uptake of potassium

Protein family

• TrkH potassium transport family (with KtrD, according to UniProt)

Paralogous protein(s)

• KtrD

Kinetic information

• the KtrA-KtrB channel has a high affinity for potassium,this is determined by KtrB PubMed

Structure

• 4J7C (the KtrA-KtrB complex) PubMed

Localization

• integral membrane protein PubMed

Expression and Regulation

Operons

• Genes: ktrA-ktrB
  Description: PubMed

  Regulatory mechanism

  • ydaO riboswitch: termination/antitermination, expression is switched off upon binding of c-di-AMP, in ydaO riboswitch

Additional information

• growth at extreme potassium limitation results in the acquisition of promoter mutations with increased ktrA-ktrB expression PubMed

Biological materials

Mutant

• MGNA-A227 (yubG::erm), available at the NBRP B. subtilis, Japan
• 1A954 ( ktrB::kan), PubMed, available at BGSC
• GHB1 (ktrA-ktrB::aphA3), available in Erhard Bremer's lab
• GP92 (ktrA-ktrB::aphA3), available in Jörg Stülke's lab PubMed
• GP2083 (ktrA-ktrB::aphA3 ktrC::tet), available in Jörg Stülke's lab PubMed
• GP2498 (ktrA-ktrB::spc kimA::cat), available in Jörg Stülke's lab
• BKE31100 (ktrB::erm trpC2) available at BGSC, PubMed, upstream reverse: _UP1_CACCTTTGTCTACATCCCTT, downstream forward: _UP4_TGATATCAAAAAAATCCGGC
• BKK31100 (ktrB::kan trpC2) available at BGSC, PubMed, upstream reverse: _UP1_CACCTTTGTCTACATCCCTT, downstream forward: _UP4_TGATATCAAAAAAATCCGGC
• GP2716 (ktrA-ktrB::spc), available in Jörg Stülke's lab
• GP3064 (ktrB::kan), available in Jörg Stülke's lab

Expression vector

• pGP2992: (IPTG inducible expression, purification in E. coli with N-terminal His-tag, in pWH844), available in Jörg Stülke's lab

FLAG-tag construct

• GP2277 (based on pGP1331), available in Jörg Stülke's lab PubMed

Labs working on this gene/protein

• Erhard Bremer, University of Marburg, Germany Homepage
• Inga Hänelt, Frankfurt, Germany Homepage
• João H Morais-Cabral, University of Porto, Portugal Homepage
• Jörg Stülke, University of Göttingen, Germany Homepage

References

Reviews

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Original publications

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