3MT5

Crystal Structure of the Human BK Gating Apparatus

Summary for 3MT5

• Entry DOI: 10.2210/pdb3mt5/pdb
• Descriptor: Potassium large conductance calcium-activated channel, subfamily M, alpha member 1, CALCIUM ION, SULFATE ION (3 entities in total)
• Functional Keywords: potassium channel, membrane protein, transport protein
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 1
• Total formula weight: 81780.55

Authors

Yuan, P.,MacKinnon, R. (deposition date: 2010-04-30, release date: 2010-06-09, Last modification date: 2024-02-21)

Primary citation

Yuan, P.,Leonetti, M.D.,Pico, A.R.,Hsiung, Y.,MacKinnon, R.
Structure of the human BK channel Ca2+-activation apparatus at 3.0 A resolution.
Science, 329:182-186, 2010

PubMed Abstract: High-conductance voltage- and Ca2+-activated K+ (BK) channels encode negative feedback regulation of membrane voltage and Ca2+ signaling, playing a central role in numerous physiological processes. We determined the x-ray structure of the human BK Ca2+ gating apparatus at a resolution of 3.0 angstroms and deduced its tetrameric assembly by solving a 6 angstrom resolution structure of a Na+-activated homolog. Two tandem C-terminal regulator of K+ conductance (RCK) domains from each of four channel subunits form a 350-kilodalton gating ring at the intracellular membrane surface. A sequence of aspartic amino acids that is known as the Ca2+ bowl, and is located within the second of the tandem RCK domains, creates four Ca2+ binding sites on the outer perimeter of the gating ring at the "assembly interface" between RCK domains. Functionally important mutations cluster near the Ca2+ bowl, near the "flexible interface" between RCK domains, and on the surface of the gating ring that faces the voltage sensors. The structure suggests that the Ca2+ gating ring, in addition to regulating the pore directly, may also modulate the voltage sensor.

PubMed: 20508092
DOI: 10.1126/science.1190414

Experimental method

X-RAY DIFFRACTION (3 Å)