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1qx7

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Crystal structure of apoCaM bound to the gating domain of small conductance Ca2+-activated potassium channel

Structural highlights

1qx7 is a 6 chain structure with sequence from Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3.09Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CALM1_RAT Calmodulin mediates the control of a large number of enzymes, ion channels, aquaporins and other proteins through calcium-binding. Among the enzymes to be stimulated by the calmodulin-calcium complex are a number of protein kinases and phosphatases. Together with CCP110 and centrin, is involved in a genetic pathway that regulates the centrosome cycle and progression through cytokinesis. Mediates calcium-dependent inactivation of CACNA1C. Positively regulates calcium-activated potassium channel activity of KCNN2.[UniProtKB:P62158]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Small conductance Ca2+-activated K+ channels (SK channels) are composed of the pore-forming alpha subunit and calmodulin (CaM). CaM binds to a region of the alpha subunit called the CaM binding domain (CaMBD), located intracellular and immediately C-terminal to the inner helix gate, in either the presence or absence of Ca2+. SK gating occurs when Ca2+ binds the N lobe of CaM thereby transmitting the signal to the attached inner helix gate to open. Here we present crystal structures of apoCaM and apoCaM/SK2 CaMBD complex. Several apoCaM crystal forms with multiple (12) packing environments reveal the same EF hand domain-swapped dimer providing potentially new insight into CaM regulation. The apoCaM/SK2 CaMBD structure, combined with our Ca2+/CaM/CaMBD structure suggests that Ca2+ binding induces folding and dimerization of the CaMBD, which causes large CaMBD-CaM C lobe conformational changes, including a >90 degrees rotation of the region of the CaMBD directly connected to the gate.

Crystal structures of apocalmodulin and an apocalmodulin/SK potassium channel gating domain complex.,Schumacher MA, Crum M, Miller MC Structure. 2004 May;12(5):849-60. PMID:15130477^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Schumacher MA, Crum M, Miller MC. Crystal structures of apocalmodulin and an apocalmodulin/SK potassium channel gating domain complex. Structure. 2004 May;12(5):849-60. PMID:15130477 doi:10.1016/j.str.2004.03.017