6V35

Cryo-EM structure of Ca2+-free hsSlo1-beta4 channel complex

Summary for 6V35

• Entry DOI: 10.2210/pdb6v35/pdb
• Related: 6V22
• EMDB information: 21025 21028 21029 21036
• Descriptor: Calcium-activated potassium channel subunit alpha-1, Calcium-activated potassium channel subunit beta-4, (1R)-2-{[(S)-{[(2S)-2,3-dihydroxypropyl]oxy}(hydroxy)phosphoryl]oxy}-1-[(hexadecanoyloxy)methyl]ethyl (9Z)-octadec-9-enoate, ... (5 entities in total)
• Functional Keywords: high conductance ca2+-activated k+ channel, slo1 channel, bk channel, maxik channel, slo1 beta subunit, beta4 subunit, transport protein
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 8
• Total formula weight: 614742.45

Authors

Tao, X.,MacKinnon, R. (deposition date: 2019-11-25, release date: 2019-12-25, Last modification date: 2024-10-30)

Primary citation

Tao, X.,MacKinnon, R.
Molecular structures of the human Slo1 K + channel in complex with beta 4.
Elife, 8:-, 2019

PubMed Abstract: Slo1 is a Ca- and voltage-activated K channel that underlies skeletal and smooth muscle contraction, audition, hormone secretion and neurotransmitter release. In mammals, Slo1 is regulated by auxiliary proteins that confer tissue-specific gating and pharmacological properties. This study presents cryo-EM structures of Slo1 in complex with the auxiliary protein, β4. Four β4, each containing two transmembrane helices, encircle Slo1, contacting it through helical interactions inside the membrane. On the extracellular side, β4 forms a tetrameric crown over the pore. Structures with high and low Ca concentrations show that identical gating conformations occur in the absence and presence of β4, implying that β4 serves to modulate the relative stabilities of 'pre-existing' conformations rather than creating new ones. The effects of β4 on scorpion toxin inhibition kinetics are explained by the crown, which constrains access but does not prevent binding.

PubMed: 31815672
DOI: 10.7554/eLife.51409

Experimental method

ELECTRON MICROSCOPY (3.5 Å)