[SPR detection of affinity of antibacterial peptides in bactericidal/permeability-increasing protein domain for endotoxin].

ABSTRACT

AIM: To study the affinity of endotoxin for three antibacterial peptides derived from N-terminal domain of bactericidal/permeability-increasing protein(BPI). METHODS: To design and synthesize three peptides from N-terminal domain of BPI, BPI22-36, BPI85-99 and BPI147-161.Surface plasmon resonance(SPR) was used to monitor the interaction between LPS/lipid A and the peptides and polymyxin B(PMB) immobilized on CM5 sensor chip. RESULTS: In three peptides, BPI147-161 was proved to have a best binding capacity with LPS/lipid A, followed by BPI85-99, but BPI22-36 could not interact with LPS/lipid A.The affinity constant K(A) of BPI147-161 with lipid A was 1.12 x 106 L/mol. In contrast, the K(A) of PMB was 5.58 x 106 L/mol. CONCLUSION: The results suggest that the peptide BPI147-161 from BPI effectively neutralize endotoxin and probably provide a novel treatment method for septic shock.