Molecular resolution imaging of an antibiotic peptide in a lipid matrix.
In this work, we show molecular resolution scanning tunneling microscopy (STM) images of gramicidin, a model antibacterial peptide, inserted into a phospholipid matrix. The resolution of the images is superior to that obtained in previous attempts to image gramicidin in a lipid environment using atomic force microscopy (AFM). This breakthrough has allowed visualization of individual peptide molecules surrounded by lipid molecules. We have observed several important features: the peptide molecules do not aggregate, the peptide molecules adopt a single conformation corresponding to a specific ion channel form, and the lipid molecules adjacent to the peptide molecules are systematically longer than those in the lipid matrix. These results constitute a new approach to obtain structural characteristics of antibiotic peptides in lipid assemblies that is necessary for the understanding of their biological activity.
Sek
Slawomir
S
Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Laredo
Thamara
T
Dutcher
John R
JR
Lipkowski
Jacek
J
D000900:Anti-Bacterial Agents / Q000737:chemistry*; D006096:Gramicidin; D007473:Ion Channels / Q000737:chemistry; D008055:Lipids / Q000737:chemistry*; D021962:Membrane Microdomains / Q000737:chemistry; D008567:Membranes, Artificial; D016252:Microscopy, Scanning Tunneling / Q000379:methods*; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry*
D000900:Anti-Bacterial Agents; D007473:Ion Channels; D008055:Lipids; D008567:Membranes, Artificial; D010455:Peptides; D006096:Gramicidin