基于PEG化“LPS/FtsZ”双靶分支肽的创制及其高效杀灭畜禽腹泻致病菌G–机制研究

本项目在前期工作基础上，应用生化、细胞和分子生物学技术分别从细胞、分子水平研究PEG化“LPS/FtsZ”双靶分支肽对畜禽腹泻G−致病菌的双靶标、多角度杀菌效能及其相关机制，研究内容：1）基于Lys分枝、PEG定点修饰（-COOH/SH）策略联合应用靶向LPS/FtsZ的LBP14、β折叠抗G−肽N6设计新型双靶分支肽α(β)2，并明确其对腹泻G−菌的高效双靶点杀菌、高稳和低毒性能；2）研究由LBP14和α螺旋广谱肽Lfcin通过Lys分枝、PEG化（-NH2/COOH）技术定向组装的双靶分支肽α(α)2靶向腹泻G−菌的特异性、选择性及其双靶标、多方位杀菌的效能；3）从分子水平初步阐明PEG化分支肽抑制“LPS/FtsZ”双靶点增强抗菌活性的分子互作机制以及多分子-多靶点之间的协同机制。这为设计新型/高效/安全多靶标抗菌肽提供了重要的理论依据，为畜禽肠道细菌性疾病的多位点协同防控另辟途径。

The “LPS/FtsZ” dual-targeting branched peptides will be generated by the Lys-branched and PEGylated techniques to control bacterial diarrhea caused by pathogenic Gram-negative bacteria (G−) in livestock and poultry. It will be focused on the following three aspects: 1) design of the novel branched peptide-α(β)2 based on one molecule of α-helical LBP14 (targeting LPS) and two molecules of β-sheet N6 (targeting FtsZ) modified with PEG at the site of -COOH/SH, and evaluation of its stability, toxicity, and resistance, bactericidal activity against diarrheagenic G− in vitro and in vivo; 2) elucidation of the antibacterial properties (including selectivity and specificity) of the branched peptide-α(α)2 against G− in vitro and in vivo, which is composed of LBP14 and α-helical Lfcin modified with PEG at the site of -NH2/COOH; 3) explanation the molecular mechanism of “LPS/FtsZ” dual-targeting branched peptides with improved antibacterial activity, including their interactions with these two targets and effects of PEGylation on their quantitative structure-activity relationship. This provides a new idea for the design and development dual/multi-targeting antimicrobial peptides against pathogenic Gram-negative bacteria s in livestock and poultry.