View source for 6hrb


==Cryo-EM structure of the KdpFABC complex in an E2 inward-facing state (state 2)==
<SX load='6hrb' size='340' side='right' viewer='molstar' caption='[[6hrb]], [[Resolution|resolution]] 4.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6hrb]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Ecoli Ecoli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6HRB OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6HRB FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=K:POTASSIUM+ION'>K</scene></td></tr>
<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=SEP:PHOSPHOSERINE'>SEP</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[6hra|6hra]]</td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">kdpA, b0698, JW0686 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=83333 ECOLI]), kdpB, b0697, JW0685 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=83333 ECOLI]), kdpC, b0696, JW0684 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=83333 ECOLI]), kdpF, b4513, JW0687 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=83333 ECOLI])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Potassium-transporting_ATPase Potassium-transporting ATPase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.6.3.12 3.6.3.12] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6hrb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6hrb OCA], [http://pdbe.org/6hrb PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6hrb RCSB], [http://www.ebi.ac.uk/pdbsum/6hrb PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6hrb ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/KDPF_ECOLI KDPF_ECOLI]] Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:23930894). This subunit may be involved in stabilization of the complex (PubMed:10608856).<ref>PMID:10608856</ref> <ref>PMID:23930894</ref>  [[http://www.uniprot.org/uniprot/KDPA_ECOLI KDPA_ECOLI]] Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:2849541, PubMed:8499455, PubMed:23930894). This subunit binds and transports the potassium across the cytoplasmic membrane (PubMed:7896809).<ref>PMID:23930894</ref> <ref>PMID:2849541</ref> <ref>PMID:7896809</ref> <ref>PMID:8499455</ref>  [[http://www.uniprot.org/uniprot/KDPC_ECOLI KDPC_ECOLI]] Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:2849541, PubMed:8499455, PubMed:23930894). This subunit acts as a catalytic chaperone that increases the ATP-binding affinity of the ATP-hydrolyzing subunit KdpB by the formation of a transient KdpB/KdpC/ATP ternary complex (PubMed:21711450).<ref>PMID:21711450</ref> <ref>PMID:23930894</ref> <ref>PMID:2849541</ref> <ref>PMID:8499455</ref>  [[http://www.uniprot.org/uniprot/KDPB_ECOLI KDPB_ECOLI]] Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:2849541, PubMed:8499455, PubMed:23930894). This subunit is responsible for energy coupling to the transport system (PubMed:16354672).<ref>PMID:16354672</ref> <ref>PMID:23930894</ref> <ref>PMID:2849541</ref> <ref>PMID:8499455</ref>  
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== Publication Abstract from PubMed ==
P-type ATPases ubiquitously pump cations across biological membranes to maintain vital ion gradients. Among those, the chimeric K(+) uptake system KdpFABC is unique. While ATP hydrolysis is accomplished by the P-type ATPase subunit KdpB, K(+) has been assumed to be transported by the channel-like subunit KdpA. A first crystal structure uncovered its overall topology, suggesting such a spatial separation of energizing and transporting units. Here, we report two cryo-EM structures of the 157 kDa, asymmetric KdpFABC complex at 3.7 A and 4.0 A resolution in an E1 and an E2 state, respectively. Unexpectedly, the structures suggest a translocation pathway through two half-channels along KdpA and KdpB, uniting the alternating-access mechanism of actively pumping P-type ATPases with the high affinity and selectivity of K(+) channels. This way, KdpFABC would function as a true chimeric complex, synergizing the best features of otherwise separately evolved transport mechanisms.

Cryo-EM structures of KdpFABC suggest a K(+) transport mechanism via two inter-subunit half-channels.,Stock C, Hielkema L, Tascon I, Wunnicke D, Oostergetel GT, Azkargorta M, Paulino C, Hanelt I Nat Commun. 2018 Nov 26;9(1):4971. doi: 10.1038/s41467-018-07319-2. PMID:30478378<ref>PMID:30478378</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6hrb" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</SX>
[[Category: Ecoli]]
[[Category: Large Structures]]
[[Category: Potassium-transporting ATPase]]
[[Category: Azkargorta, M]]
[[Category: Haenelt, I]]
[[Category: Hielkema, L]]
[[Category: Oostergetel, G T]]
[[Category: Paulino, C]]
[[Category: Stock, C]]
[[Category: Tascon, I]]
[[Category: Wunnicke, D]]
[[Category: Membrane protein]]