Gating of the MlotiK1 potassium channel involves large rearrangements of the cyclic nucleotide-binding domains.
Proc Natl Acad Sci U S A
; 108(51): 20802-7, 2011 Dec 20.
Article
en En
| MEDLINE
| ID: mdl-22135457
ABSTRACT
Cyclic nucleotide-regulated ion channels are present in bacteria, plants, vertebrates, and humans. In higher organisms, they are closely involved in signaling networks of vision and olfaction. Binding of cAMP or cGMP favors the activation of these ion channels. Despite a wealth of structural and studies, there is a lack of structural data describing the gating process in a full-length cyclic nucleotide-regulated channel. We used high-resolution atomic force microscopy (AFM) to directly observe the conformational change of the membrane embedded bacterial cyclic nucleotide-regulated channel MlotiK1. In the nucleotide-bound conformation, the cytoplasmic cyclic nucleotide-binding (CNB) domains of MlotiK1 are disposed in a fourfold symmetric arrangement forming a pore-like vestibule. Upon nucleotide-unbinding, the four CNB domains undergo a large rearrangement, stand up by â¼1.7 nm, and adopt a structurally variable grouped conformation that closes the cytoplasmic vestibule. This fully reversible conformational change provides insight into how CNB domains rearrange when regulating the potassium channel.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Canales de Potasio
/
Mesorhizobium
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2011
Tipo del documento:
Article
País de afiliación:
Suiza