2KXL

Solution structure of a bacterial cyclic nucleotide-activated K+ channel binding domain in the unliganded state

Summary for 2KXL

• Entry DOI: 10.2210/pdb2kxl/pdb
• Related: 2K0G
• Descriptor: Cyclic nucleotide-gated potassium channel mll3241 (1 entity in total)
• Functional Keywords: cyclic nucleotide binding domain (cnbd), ion channel, protein phosphate binding cassette in the apo state, helical portion, beta barrel core, membrane protein
• Biological source: Mesorhizobium loti
• Cellular location: Cell membrane; Multi-pass membrane protein: Q98GN8
• Total number of polymer chains: 1
• Total formula weight: 14983.22

Authors

Schunke, S.,Stoldt, M.,Willbold, D. (deposition date: 2010-05-10, release date: 2011-04-20, Last modification date: 2024-05-01)

Primary citation

Schunke, S.,Stoldt, M.,Lecher, J.,Kaupp, U.B.,Willbold, D.
Structural insights into conformational changes of a cyclic nucleotide-binding domain in solution from Mesorhizobium loti K1 channel.
Proc.Natl.Acad.Sci.USA, 108:6121-6126, 2011

PubMed Abstract: Cyclic nucleotide-sensitive ion channels, known as HCN and CNG channels, are activated by binding of ligands to a domain (CNBD) located on the cytoplasmic side of the channel. The underlying mechanisms are not well understood. To elucidate the gating mechanism, structures of both the ligand-free and -bound CNBD are required. Several crystal structures of the CNBD from HCN2 and a bacterial CNG channel (MloK1) have been solved. However, for HCN2, the cAMP-free and -bound state did not reveal substantial structural rearrangements. For MloK1, structural information for the cAMP-free state has only been gained from mutant CNBDs. Moreover, in the crystal, the CNBD molecules form an interface between dimers, proposed to be important for allosteric channel gating. Here, we have determined the solution structure by NMR spectroscopy of the cAMP-free wild-type CNBD of MloK1. A comparison of the solution structure of cAMP-free and -bound states reveals large conformational rearrangement on ligand binding. The two structures provide insights on a unique set of conformational events that accompany gating within the ligand-binding site.

PubMed: 21430265
DOI: 10.1073/pnas.1015890108

Experimental method

SOLUTION NMR