Open AccessCoiled-coil formation of the membrane-fusion K/E peptides viewed by electron paramagnetic resonance
Author(s) -
Pravin Kumar,
Martin van Son,
Tingting Zheng,
Dayenne Valdink,
J. Raap,
Alexander Kros,
Martina Huber
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0191197
Subject(s) - electron paramagnetic resonance , membrane , site directed spin labeling , peptide , chemistry , fusion , zipper , pulsed epr , coiled coil , resonance (particle physics) , crystallography , nuclear magnetic resonance , spin label , biophysics , physics , magnetic resonance imaging , biochemistry , spin echo , atomic physics , biology , medicine , linguistics , philosophy , algorithm , radiology , computer science
The interaction of the complementary K ( Ac-(KIAALKE) 3 -GW-NH 2 ) and E ( Ac-(EIAALEK) 3 -GY-NH 2 ) peptides, components of the zipper of an artificial membrane fusion system ( Robson Marsden H . et al . Angew Chemie Int Ed . 2009 ) is investigated by electron paramagnetic resonance (EPR). By frozen solution continuous-wave EPR and double electron-electron resonance (DEER), the distance between spin labels attached to the K- and to the E-peptide is measured. Three constructs of spin-labelled K- and E-peptides are used in five combinations for low temperature investigations. The K/E heterodimers are found to be parallel, in agreement with previous studies. Also, K homodimers in parallel orientation were observed, a finding that was not reported before. Comparison to room-temperature, solution EPR shows that the latter method is less specific to detect this peptide-peptide interaction. Combining frozen solution cw-EPR for short distances (1.8 nm to 2.0 nm) and DEER for longer distances thus proves versatile to detect the zipper interaction in membrane fusion. As the methodology can be applied to membrane samples, the approach presented suggests itself for in-situ studies of the complete membrane fusion process, opening up new avenues for the study of membrane fusion.