National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM43949
米国
引用
ジャーナル: Elife / 年: 2019 タイトル: Molecular structures of the human Slo1 K channel in complex with β4. 著者: Xiao Tao / Roderick MacKinnon / 要旨: 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 ...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.
名称: Ca2+-free hsSlo1 channel / タイプ: COMPLEX 詳細: human high conductance Ca2+-activated K+ channel Slo1 (BK) in the absence of Calcium Entity ID: all / 由来: RECOMBINANT
分子量
実験値: NO
由来(天然)
生物種: Homo sapiens (ヒト)
由来(組換発現)
生物種: Homo sapiens (ヒト) / 株: HEK293S GnTI-
緩衝液
pH: 8
緩衝液成分
ID
濃度
名称
式
Buffer-ID
1
450mM
potassiumchloride
KCl
1
2
20mM
Tris
C4H11NO3
1
3
0.5mM
Digitonin
C56H92O29
1
4
5mM
EGTA
C14H24N2O10
1
5
15mM
magnesiumchloride
MgCl2
1
試料
濃度: 8.5 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES