3SJQ

Crystal structure of a small conductance potassium channel splice variant complexed with calcium-calmodulin

Summary for 3SJQ

• Entry DOI: 10.2210/pdb3sjq/pdb
• Descriptor: Calmodulin, Small conductance calcium-activated potassium channel protein 2, CALCIUM ION, ... (7 entities in total)
• Functional Keywords: protein-protein complex, ef hand, calmodulin, calcium binding, metal binding protein
• Biological source: Rattus norvegicus (rat); More
• Cellular location: Cytoplasm, cytoskeleton, spindle: P62161; Membrane; Multi-pass membrane protein: P70604
• Total number of polymer chains: 4
• Total formula weight: 56777.87

Authors

Zhang, M.,Pascal, J.M.,Zhang, J.-F. (deposition date: 2011-06-21, release date: 2012-05-30, Last modification date: 2023-09-13)

Primary citation

Zhang, M.,Abrams, C.,Wang, L.,Gizzi, A.,He, L.,Lin, R.,Chen, Y.,Loll, P.J.,Pascal, J.M.,Zhang, J.F.
Structural basis for calmodulin as a dynamic calcium sensor.
Structure, 20:911-923, 2012

PubMed Abstract: Calmodulin is a prototypical and versatile Ca(2+) sensor with EF hands as its high-affinity Ca(2+) binding domains. Calmodulin is present in all eukaryotic cells, mediating Ca(2+)-dependent signaling. Upon binding Ca(2+), calmodulin changes its conformation to form complexes with a diverse array of target proteins. Despite a wealth of knowledge on calmodulin, little is known on how target proteins regulate calmodulin's ability to bind Ca(2+). Here, we take advantage of two splice variants of SK2 channels, which are activated by Ca(2+)-bound calmodulin but show different sensitivity to Ca(2+) for their activation. Protein crystal structures and other experiments show that, depending on which SK2 splice variant it binds to, calmodulin adopts drastically different conformations with different affinities for Ca(2+) at its C-lobe. Such target protein-induced conformational changes make calmodulin a dynamic Ca(2+) sensor capable of responding to different Ca(2+) concentrations in cellular Ca(2+) signaling.

PubMed: 22579256
DOI: 10.1016/j.str.2012.03.019

Experimental method

X-RAY DIFFRACTION (1.9 Å)