Intermolecular packing and alignment in an ordered beta-hairpin antimicrobial peptide aggregate from 2D solid-state NMR.

摘要: The aggregation and packing of a membrane-disruptive beta-hairpin antimicrobial peptide, protegrin-1 (PG-1), in the solid state are investigated to understand its oligomerization hydrogen-bonding propensity. Incubation PG-1 phosphate buffer saline produced well-ordered nanometer-scale aggregates, as indicated by 13C 15N NMR line widths, chemical shifts, electron microscopy. Two-dimensional 1H spin diffusion experiments using C-terminus strand N-terminus labeled peptides indicate that molecules these ordered aggregates oriented parallel each other with like strands lining intermolecular interface. In comparison, disordered lyophilized peptide samples randomly packed both antiparallel alignments. show significant immobilization Phe ring near beta-turn, further supporting structural ordering. found is consistent lipid bilayers. This solid-state approach may be useful for determining quaternary structure general gaining insights into bilayers particular.