Referenced in: none

Automatically associated channels: HCN2

Title: Mapping the structure and conformational movements of proteins with transition metal ion FRET.

Authors: Justin W Taraska, Michael C Puljung, Nelson B Olivier, Galen E Flynn, William N Zagotta

Journal, date & volume: Nat. Methods, 2009 Jul , 6, 532-7

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/19525958

Abstract
Visualizing conformational dynamics in proteins has been difficult, and the atomic-scale motions responsible for the behavior of most allosteric proteins are unknown. Here we report that fluorescence resonance energy transfer (FRET) between a small fluorescent dye and a nickel ion bound to a dihistidine motif can be used to monitor small structural rearrangements in proteins. This method provides several key advantages over classical FRET, including the ability to measure the dynamics of close-range interactions, the use of small probes with short linkers, a low orientation dependence, and the ability to add and remove unique tunable acceptors. We used this 'transition metal ion FRET' approach along with X-ray crystallography to determine the structural changes of the gating ring of the mouse hyperpolarization-activated cyclic nucleotide-regulated ion channel HCN2. Our results suggest a general model for the conformational switch in the cyclic nucleotide-binding site of cyclic nucleotide-regulated ion channels.