open access

https://hdl.handle.net/2115/64933

Lipopolysaccharide-bound structure of the antimicrobial peptide cecropin P1 determined by nuclear magnetic resonance spectroscopy

英語

transferred nuclear Overhauser effect

2016-04

Wiley-Blackwell

Journal of peptide science

22(4)

214-221

Antimicrobial peptides (AMPs) are components of the innate immune system and may be potential alternatives to conventional antibiotics because they exhibit broad-spectrum antimicrobial activity. The AMP cecropin P1 (CP1), isolated from nematodes found in the stomachs of pigs, is known to exhibit antimicrobial activity against Gram-negative bacteria. In this study, we investigated the interaction between CP1 and lipopolysaccharide (LPS), which is the main component of the outer membrane of Gram-negative bacteria, using circular dichroism (CD) and nuclear magnetic resonance (NMR). CD results showed that CP1 formed an -helical structure in a solution containing LPS. For NMR experiments, we expressed N-15-labeled and C-13-labeled CP1 in bacterial cells and successfully assigned almost all backbone and side-chain proton resonance peaks of CP1 in water for transferred nuclear Overhauser effect (Tr-NOE) experiments in LPS. We performed N-15-edited and C-13-edited Tr-NOE spectroscopy for CP1 bound to LPS. Tr-NOE peaks were observed at the only C-terminal region of CP1 in LPS. The results of structure calculation indicated that the C-terminal region (Lys15-Gly29) formed the well-defined -helical structure in LPS. Finally, the docking study revealed that Lys15/Lys16 interacted with phosphate at glucosamine I via an electrostatic interaction and that Ile22/Ile26 was in close proximity with the acyl chain of lipid A. Copyright (c) 2016 European Peptide Society and John Wiley & Sons, Ltd.

学術雑誌論文

Accepted Manuscript

1075-2617