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.
Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Slawomir
S
Sek
Thamara
T
Laredo
John R
JR
Dutcher
Jacek
J
Lipkowski
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