kimA

168

high-affinity potassium transporter (uptake)

locus: BSU_04320

Molecular weight: 66.60 kDa

pI: 9.93

Protein length: 607 aa

Gene length: 1824 bp

function: potassium uptake

product: high-affinity K⁺/H⁺ symporter

essential: no

synonyms: kimA, ydaO

List of homologs in different organisms, belongs to COG0531 (Galperin et al., 2021)

Gene

Coordinates: 486,432  488,255

Phenotypes of a mutant

• a [gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA] [gene|92D0275E0768780F782F4B3724BC5181E436B6B1|ktrA] [gene|A287B9771A56D03ADCA603C1969CBF03DCB10E95|ktrB] mutant requires high potassium concentrations on minimal medium with ammonium as nitrogen source [pubmed|28420751,28679749]
• inactivation of [gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA] facilitates the adaptation a strain lacking c-di-AMP to growth on complex medium under aerobic conditions [pubmed|33481774]
• significantly delayed osmoadaptation to high NaCl [pubmed|35164567]
• a [gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA] [gene|92D0275E0768780F782F4B3724BC5181E436B6B1|ktrA]-[gene|A287B9771A56D03ADCA603C1969CBF03DCB10E95|ktrB] double mutant is unable to adapt to the presence of 1.2 M NaCl [pubmed|35164567]

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The protein

Catalyzed reaction/ biological activity

• K⁺/H⁺ symport [pubmed|32005818,28420751]

Protein family

• KUP family (single member) [pubmed|32005818]
• [wiki|amino acid-polyamine-organocation (APC) superfamily] (according to UniProt)

[wiki|Domains]

• 12 trans-membrane helices at the N-terminus [pubmed|32005818]
• C-terminal cytoplasmic domain [pubmed|28420751]

Structure

• [PDB|8B71] (KimA dimer with bound c-di-AMP) [pubmed|37344476]
• [PDB|6S3K] [pubmed|32005818]
• [PDB|8B70] (KimA dimer with bound c-di-AMP) [pubmed|37344476]
• [AF|P96589]

Effectors of protein activity

• activity is inhibited upon binding of c-di-AMP [pubmed|37344476,31061098]
• c-di-AMP binds to the C-terminal cytoplasmic domain of KimA [pubmed|37344476]

Kinetic information

• K_M: 215 µM [pubmed|32005818]
• V_max 245 nmol min⁻¹ mg⁻¹ [pubmed|32005818]

[wiki|Localization]

• cell membrane [pubmed|30452022]

Expression and Regulation

Operons

• genes: [gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA]

  description: [Pubmed|22383849]

  regulation

  • expressed at low potassium concentration ([regulon|ydaO riboswitch|]) [Pubmed|28420751]

  regulatory mechanism

  • c-di-AMP Riboswitch: RNA switch, expression is switched off upon binding of c-di-AMP (formed at high potassium concentration) [pubmed|28420751], in [regulon|other_regulator:c-di-AMP Riboswitch|c-di-AMP Riboswitch]

Biological materials

Mutant

• MGNA-C090 (kimA::erm), available at the [https://shigen.nig.ac.jp/bsub/resource/strainGeneDisrupted/detail/2088 NBRP B. subtilis, Japan]
• 1A688 (''[gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA]''::''erm''), available at [http://pasture.asc.ohio-state.edu/BGSC/getdetail.cfm?bgscid=1A688&Search=1A688 BGSC]
• GP93 (Δ[gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA]::''cat''), available in [wiki|Jörg Stülke]'s lab [pubmed|28420751]
• JH642 and its derivatives: natural deletion of the 18 kb [gene|467E9CF20B545A976614968E7DD5497F9390D344|ydzA]-[gene|353DADE8E57A0F1895CCEB62701F9273EEB5EB45|mntH] region encompassing the genes [gene|467E9CF20B545A976614968E7DD5497F9390D344|ydzA]-[gene|7D5327BD1DD5FD5F90B2C849589923AA3D8B20EF|topB]-[gene|69DEE29383E40F49890CC8314DFBF56D70D35113|ydaJ]-[gene|70ED3CE683F3A3F785480F40986CABE7729C17C7|ydaK]-[gene|28D80C5497AE29A24AD6B9A1A713A2B3915F2CED|ydaL]-[gene|961538BEDD27C24FC073AFB7AB3268E3D46783CC|ydaM]-[gene|ADE0122D8FFF2F78B6D21031B7D02A323A13ED63|ydaN]-[gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA]-[gene|6085BDAD40F719555EA4EEA7BBAD74103BD03D0F|mutT]-[gene|2883FC60CD69948D5C43BDDFEFBE7A1CA7C743C7|ydaP]-[gene|87834D5C47064BEFF26F086A8202C311F28F9D38|ydzK]-[gene|search|mntH ][pubmed|18670626]
• BKE04320 (Δ[gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA]::erm  trpC2) available at [http://bgsc.org/getdetail.php?bgscid=BKE04320 BGSC],  [Pubmed|28189581], upstream reverse: _UP1_CATCGATGTCTTCCCCTTTT,  downstream forward: _UP4_TAAAGCTCTAGGACCAAGGG
• BKK04320 (Δ[gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA]::kan  trpC2) available at [http://bgsc.org/getdetail.php?bgscid=BKK04320 BGSC],  [Pubmed|28189581], upstream reverse: _UP1_CATCGATGTCTTCCCCTTTT,  downstream forward: _UP4_TAAAGCTCTAGGACCAAGGG
• GP2720 (Δ[gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA]::''spc''), available in [wiki|Jörg Stülke]'s lab
• GP2721 (Δ[gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA]::''ermC''), available in [wiki|Jörg Stülke]'s lab
• GP2498 (Δ[gene|5968E6D4D7378C69EC3E1E05B285069123AA1FD3|kimA]::''cat'' [gene|92D0275E0768780F782F4B3724BC5181E436B6B1|ktrA]-[gene|A287B9771A56D03ADCA603C1969CBF03DCB10E95|ktrB]::''spc''), available in [wiki|Jörg Stülke]'s lab

Expression vectors

• pGP2913 (N-terminal His-tag, expression in ''E. coli'', in [wiki|pWH844]), available in [wiki|Jörg Stülke]'s lab [pubmed|28420751]

FLAG-tag construct

• GP2405 ''ydaO-3xFLAG spc'' (based on [wiki|pGP1331]), available in [wiki|Jörg Stülke]'s lab [pubmed|28420751]

lacZ fusion

• BP144 (based on [wiki|pAC5]), available in [wiki|Fabian Commichau]' and [wiki|Jörg Stülke]'s labs [pubmed|28420751]

labs

• [wiki|Jörg Stülke], University of Göttingen, Germany [http://genmibio.uni-goettingen.de Homepage]
• [wiki|Inga Hänelt], Frankfurt, Germany [https://www.biochem.uni-frankfurt.de/index.php?id=298 Homepage]

References

Reviews

• 25869574,28825218,32472931,32603625,33798529

Original Publications

• 15096624,20511502,23086297,24141192,25086509,25086507,28420751,28679749,30452022,31061098,31506295,32005818,32253343,33481774,35164567,37344476