This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
6hra is a 4 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
[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).[1][2][3][4] [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).[5][6][7][8] [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).[9][10] [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).[11][12][13][14]
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[15]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Haupt M, Bramkamp M, Heller M, Coles M, Deckers-Hebestreit G, Herkenhoff-Hesselmann B, Altendorf K, Kessler H. The holo-form of the nucleotide binding domain of the KdpFABC complex from Escherichia coli reveals a new binding mode. J Biol Chem. 2006 Apr 7;281(14):9641-9. Epub 2005 Dec 14. PMID:16354672 doi:http://dx.doi.org/10.1074/jbc.M508290200
↑ Damnjanovic B, Weber A, Potschies M, Greie JC, Apell HJ. Mechanistic analysis of the pump cycle of the KdpFABC P-type ATPase. Biochemistry. 2013 Aug 20;52(33):5563-76. doi: 10.1021/bi400729e. Epub 2013 Aug, 9. PMID:23930894 doi:http://dx.doi.org/10.1021/bi400729e
↑ Siebers A, Altendorf K. The K+-translocating Kdp-ATPase from Escherichia coli. Purification, enzymatic properties and production of complex- and subunit-specific antisera. Eur J Biochem. 1988 Dec 1;178(1):131-40. PMID:2849541
↑ Kollmann R, Altendorf K. ATP-driven potassium transport in right-side-out membrane vesicles via the Kdp system of Escherichia coli. Biochim Biophys Acta. 1993 Jun 10;1143(1):62-6. PMID:8499455
↑ Damnjanovic B, Weber A, Potschies M, Greie JC, Apell HJ. Mechanistic analysis of the pump cycle of the KdpFABC P-type ATPase. Biochemistry. 2013 Aug 20;52(33):5563-76. doi: 10.1021/bi400729e. Epub 2013 Aug, 9. PMID:23930894 doi:http://dx.doi.org/10.1021/bi400729e
↑ Siebers A, Altendorf K. The K+-translocating Kdp-ATPase from Escherichia coli. Purification, enzymatic properties and production of complex- and subunit-specific antisera. Eur J Biochem. 1988 Dec 1;178(1):131-40. PMID:2849541
↑ Buurman ET, Kim KT, Epstein W. Genetic evidence for two sequentially occupied K+ binding sites in the Kdp transport ATPase. J Biol Chem. 1995 Mar 24;270(12):6678-85. PMID:7896809
↑ Kollmann R, Altendorf K. ATP-driven potassium transport in right-side-out membrane vesicles via the Kdp system of Escherichia coli. Biochim Biophys Acta. 1993 Jun 10;1143(1):62-6. PMID:8499455
↑ Gassel M, Mollenkamp T, Puppe W, Altendorf K. The KdpF subunit is part of the K(+)-translocating Kdp complex of Escherichia coli and is responsible for stabilization of the complex in vitro. J Biol Chem. 1999 Dec 31;274(53):37901-7. PMID:10608856
↑ Damnjanovic B, Weber A, Potschies M, Greie JC, Apell HJ. Mechanistic analysis of the pump cycle of the KdpFABC P-type ATPase. Biochemistry. 2013 Aug 20;52(33):5563-76. doi: 10.1021/bi400729e. Epub 2013 Aug, 9. PMID:23930894 doi:http://dx.doi.org/10.1021/bi400729e
↑ Irzik K, Pfrotzschner J, Goss T, Ahnert F, Haupt M, Greie JC. The KdpC subunit of the Escherichia coli K+-transporting KdpB P-type ATPase acts as a catalytic chaperone. FEBS J. 2011 Sep;278(17):3041-53. doi: 10.1111/j.1742-4658.2011.08224.x. Epub, 2011 Jul 22. PMID:21711450 doi:http://dx.doi.org/10.1111/j.1742-4658.2011.08224.x
↑ Damnjanovic B, Weber A, Potschies M, Greie JC, Apell HJ. Mechanistic analysis of the pump cycle of the KdpFABC P-type ATPase. Biochemistry. 2013 Aug 20;52(33):5563-76. doi: 10.1021/bi400729e. Epub 2013 Aug, 9. PMID:23930894 doi:http://dx.doi.org/10.1021/bi400729e
↑ Siebers A, Altendorf K. The K+-translocating Kdp-ATPase from Escherichia coli. Purification, enzymatic properties and production of complex- and subunit-specific antisera. Eur J Biochem. 1988 Dec 1;178(1):131-40. PMID:2849541
↑ Kollmann R, Altendorf K. ATP-driven potassium transport in right-side-out membrane vesicles via the Kdp system of Escherichia coli. Biochim Biophys Acta. 1993 Jun 10;1143(1):62-6. PMID:8499455
↑ Stock C, Hielkema L, Tascon I, Wunnicke D, Oostergetel GT, Azkargorta M, Paulino C, Hanelt I. Cryo-EM structures of KdpFABC suggest a K(+) transport mechanism via two inter-subunit half-channels. Nat Commun. 2018 Nov 26;9(1):4971. doi: 10.1038/s41467-018-07319-2. PMID:30478378 doi:http://dx.doi.org/10.1038/s41467-018-07319-2
