Resurrecting inactive antimicrobial peptide from LPS trap : activity, LPS-interactions and conformations of a hybrid peptide of temporin B and beta-boomerang motif.

• Main Author: Goh, Su-Ann.
• Other Authors: Surajit Bhattacharyya
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Science
• Online Access: http://hdl.handle.net/10356/52495
• Institution: Nanyang Technological University

Antimicrobial peptides are short defensive peptides that represent a promising therapeutic option to eradicate antimicrobial resistant strains that has long since been increasing in number. Temporin B is a natural antimicrobial peptide that has shown reduced efficacy on Gram-negative strains due to its tendency to oligomerize on the lipopolysaccharide feature of the outer membrane. Conjugating Temporin B to a synthetic lipopolysaccharide binding motif termed β-boomerang domain, formed a synthetic peptide, LG21, with vastly improved antimicrobial activity. In this study, we attempt to understand the role of Temporin B component of LG21 by truncating the Temporin B portion, forming synthetic peptide LG14. LG14 was shown to have reduced antimicrobial activity but was still able to permeate the bacterial outer membrane and inner membrane, though comparatively less efficient in the latter. Fluorescence assays highlighted limited discrimination between eukaryotic membrane mimic and bacterial inner membrane mimic. Structural elucidation by circular dichroism and nuclear magnetic resonance spectroscopy of LG14 were in agreement on an α-helical conformation at bound state. NMR also indicated that the α-helix has little amphipathicity. Collectively, these results demonstrate that Temporin B played a role in conferring LG21 with antimicrobial activity especially in recognition and perturbation of the bacterial inner membrane.