ISDA

Deposition Date 2001-12-07

Release Date 2001-12-14

Last Version Date 2024-05-22

Entry Detail

PDB ID:

1KKD

Keywords:

SIGNALING PROTEIN

Title:

Solution structure of the calmodulin binding domain (CaMBD) of small conductance Ca2+-activated potassium channels (SK2)

Biological Source:

Source Organism:

Rattus norvegicus (Taxon ID: 10116)

Host Organism:

Escherichia coli BL21(DE3)

Method Details:

Experimental Method:

SOLUTION NMR

Conformers Calculated:

300

Conformers Submitted:

Selection Criteria:

structures with the least restraint violations,target function

Download Validation Report

Macromolecular Entities

Protein Blast

Polymer Type:polypeptide(L)
Molecule:Small conductance calcium-activated potassium channel protein 2
Gene (Uniprot):Kcnn2
Chain IDs:A
Chain Length:102
Number of Molecules:1
Biological Source:Rattus norvegicus

UniProt ID:P70604 Pfam ID:PF02888

Ligand Molecules

Primary Citation

A helical region in the C terminus of small-conductance Ca2+-activated K+ channels controls assembly with apo-calmodulin.

Wissmann, R, Bildl, W, Neumann, H, Rivard, A.F, Klocker, N, Weitz, D, Schulte, U, Adelman, J.P, Bentrop, D, Fakler, B, Keen, J.E, Khawaled, R, Farrens, D.L, Neelands, T, Rivard, A, Bond, C.T, Janowsky, A, Fakler, B, Adelman, J.P, Maylie, J, Xia, X.-M, Fakler, B, Rivard, A, Wayman, G, Johnson-Pais, T, Keen, J.E, Ishii, T, Hirschberg, B, Bond, C.T, Lutsenko, S, Maylie, J, Adelman, J.P, Schumacher, M.A, Rivard, A.F, Baechinger, H.P, Adelman, J.P.Show

J.Biol.Chem. 277 4558 4564 (2002)

PMID: 11723128 DOI: 10.1074/jbc.M109240200

Abstact

Small conductance Ca(2+)-activated potassium (SK) channels underlie the afterhyperpolarization that follows the action potential in many types of central neurons. SK channels are voltage-independent and gated solely by intracellular Ca(2+) in the submicromolar range. This high affinity for Ca(2+) results from Ca(2+)-independent association of the SK alpha-subunit with calmodulin (CaM), a property unique among the large family of potassium channels. Here we report the solution structure of the calmodulin binding domain (CaMBD, residues 396-487 in rat SK2) of SK channels using NMR spectroscopy. The CaMBD exhibits a helical region between residues 423-437, whereas the rest of the molecule lacks stable overall folding. Disruption of the helical domain abolishes constitutive association of CaMBD with Ca(2+)-free CaM, and results in SK channels that are no longer gated by Ca(2+). The results show that the Ca(2+)-independent CaM-CaMBD interaction, which is crucial for channel function, is at least in part determined by a region different in sequence and structure from other CaM-interacting proteins.

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Primary Citation of related structures