Chemical labeling strategy with (R)- and (S)-trifluoromethylalanine for solid state 19F NMR analysis of peptaibols in membranes.
Substitution of a single Aib-residue in a peptaibol with (R)- and (S)-trifluoromethylalanine yields two local orientational constraints theta by solid state (19)F NMR. The structure of the membrane-perturbing antibiotic alamethicin in DMPC bilayers was analyzed in terms of two angles tau and rho from six such constraints, showing that the N-terminus (up to a kink at Pro14) is folded as an alpha-helix, tilted away from the membrane normal by 8 degrees, and assembled as an oligomer. The new (19)F NMR label CF(3)-Ala has thus been demonstrated to be highly sensitive, virtually unperturbing, and ideally suited to characterize peptaibols in membranes.
Maisch
Daniel
D
Karlsruhe Institute of Technology, Institut für Organische Chemie, Fritz-Haber-Weg 6, 76133 Karlsruhe, Germany.
Wadhwani
Parvesh
P
Afonin
Sergii
S
Böttcher
Christoph
C
Koksch
Beate
B
Ulrich
Anne S
AS
D000409:Alanine / Q000031:analogs & derivatives* / Q000737:chemistry; D002942:Circular Dichroism; D005461:Fluorine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D054848:Peptaibols / Q000737:chemistry*; D013237:Stereoisomerism
D054848:Peptaibols; C507723:alpha-trifluoromethylalanine; D005461:Fluorine; D000409:Alanine