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==Solution structure of the cytoplasmic N-terminus of the BK beta-subunit KCNMB2==
<StructureSection load='1jo6' size='340' side='right'caption='[[1jo6]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1jo6]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JO6 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1JO6 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1jo6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jo6 OCA], [https://pdbe.org/1jo6 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1jo6 RCSB], [https://www.ebi.ac.uk/pdbsum/1jo6 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1jo6 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/KCMB2_HUMAN KCMB2_HUMAN] Regulatory subunit of the calcium activated potassium KCNMA1 (maxiK) channel. Modulates the calcium sensitivity and gating kinetics of KCNMA1, thereby contributing to KCNMA1 channel diversity. Acts as a negative regulator that confers rapid and complete inactivation of KCNMA1 channel complex. May participate in KCNMA1 inactivation in chromaffin cells of the adrenal gland or in hippocampal CA1 neurons.<ref>PMID:10097176</ref> <ref>PMID:10377337</ref> 
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== Publication Abstract from PubMed ==
The auxiliary beta-subunit KCNMB2 (beta(2)) endows the non-inactivating large conductance Ca(2+)- and voltage-dependent potassium (BK) channel with fast inactivation. This process is mediated by the N terminus of KCNMB2 and closely resembles the "ball-and-chain"-type inactivation observed in voltage-gated potassium channels. Here we investigated the solution structure and function of the KCNMB2 N terminus (amino acids 1-45, BKbeta(2)N) using NMR spectroscopy and patch clamp recordings. BKbeta(2)N completely inactivated BK channels when applied to the cytoplasmic side; its interaction with the BK alpha-subunit is characterized by a particularly slow dissociation rate and an affinity in the upper nanomolar range. The BKbeta(2)N structure comprises two domains connected by a flexible linker: the pore-blocking "ball domain" (formed by residues 1-17) and the "chain domain" (between residues 20-45) linking it to the membrane segment of KCNMB2. The ball domain is made up of a flexible N terminus anchored at a well ordered loop-helix motif. The chain domain consists of a 4-turn helix with an unfolded linker at its C terminus. These structural properties explain the functional characteristics of BKbeta(2)N-mediated inactivation.

NMR structure of the "ball-and-chain" domain of KCNMB2, the beta 2-subunit of large conductance Ca2+- and voltage-activated potassium channels.,Bentrop D, Beyermann M, Wissmann R, Fakler B J Biol Chem. 2001 Nov 9;276(45):42116-21. Epub 2001 Aug 21. PMID:11517232<ref>PMID:11517232</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 1jo6" style="background-color:#fffaf0;"></div>

==See Also==
*[[Potassium channel 3D structures|Potassium channel 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Bentrop D]]
[[Category: Beyermann M]]
[[Category: Fakler B]]
[[Category: Wissmann R]]