Antibacterial activity of linear peptides spanning the carboxy-terminal beta-sheet domain of arthropod defensins.
The antibacterial activity of peptides without disulfide bridges, spanning the carboxy-terminal segment of arthropod defensins, has been investigated. Although all the peptides have net positive charges, they exhibited varying antibacterial potencies and spectra. Atomic force and fluorescence microscopic analyses indicate that the peptides exert their activity by permeabilizing the outer and inner membranes of Gram-negative bacteria such as Escherichia coli. It appears that the plasticity observed in the activity of mammalian defensins with respect to sequence, number of disulfide bridges or net positive charge, is also observed in insect defensins.
Varkey
Jobin
J
Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India.
Singh
Shashi
S
Nagaraj
Ramakrishnan
R
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001181:Arthropods / Q000737:chemistry*; D001419:Bacteria / Q000187:drug effects*; D023082:Defensins / Q000235:genetics / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D016415:Sequence Alignment
D000900:Anti-Bacterial Agents; D023082:Defensins; D010455:Peptides