杀菌/渗透增强蛋白功能区抗菌肽与内毒素亲和性的SPR技术检测

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

目的:研究杀菌/渗透增强蛋白(BPI)不同功能区抗菌肽与内毒素(LPS)结合的能力。方法:设计、合成来自杀菌/渗透增强蛋白N端不同功能区的3段抗菌肽,分别为BPI22-36、BPI85-99和BPI147-161,将其固定于CM5蛋白质芯片上,使用表面等离子共振(SPR)仪检测3种抗菌肽与LPS和类脂A(Lipid A)相互作用的情况。结果:3种抗菌肽中,BPI147-161与LPS和Lipid A结合的能力最强,BPI85-99次之,但BPI22-36与其不结合;BPI147-161与Lipid A的亲和常数KA为1.12×106L/mol,相比,多黏菌素B(PMB)的亲和常数KA为5.58×106L/mol。结论:来自杀菌/渗透增强蛋白的抗菌肽BPI147-161能有效地中和内毒素,这可能为败血症休克的治疗提供一种新的策略。

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 KA of BPI147-161 with lipid A was 1.12×106 L/mol.In contrast,the KA of PMB was 5.58×106L/mol.CONCLUSION： The rusults suggests that the peptid BPI147-161 from BPI effectively neutralize endotoxin and probably provide a novel treatment method for septic shock.