Monitoring ion channel conformations in membranes utilizing a novel dual fluorescence quenching approach.
The linear peptide gramicidin forms prototypical ion channels specific for monovalent cations and has been extensively used to study the organization, dynamics, and function of membrane-spanning channels. We have analyzed the localization of the functionally important tryptophan residues of the membrane-bound channel and non-channel conformations of gramicidin utilizing a novel dual fluorescence quenching approach [G.A. Caputo, E. London, Biochemistry 42 (2003) 3265-3274]. In this paper, we show for the first time that the dual quenching approach is applicable to multiple tryptophan containing functional ion channel peptides such as gramicidin. Importantly, dual quenching is found to be sensitive to the membrane-bound conformations of this important model ion channel.
Kelkar
Devaki A
DA
Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
Chattopadhyay
Amitabha
A
D006096:Gramicidin / Q000737:chemistry*; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry*; D008051:Lipid Bilayers / Q000032:analysis / Q000737:chemistry*; D008560:Membrane Fluidity; D008567:Membranes, Artificial; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence / Q000379:methods*
D007473:Ion Channels; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D006096:Gramicidin