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
