Beijing Higher Institution Engineering Research Center of Food Additives and Ingredients, School of Food and Chemical Engineering , Beijing Technology and Business University , Beijing 100048 , China.
J Agric Food Chem. 2018 Aug 29;66(34):9138-9146. doi: 10.1021/acs.jafc.8b02489. Epub 2018 Aug 16.
The present study investigated a novel lysozyme ApLyz from the Chinese oak silkmoth, Antheraea pernyi, for its active expression with N- or C-terminus fused to the yeast cell surface, and the antimicrobial activities of the corresponding expressed lysozymes were evaluated. The bactericidal activity of C-terminal fusion of ApLyz surpassed that of the N-terminal fusion, which revealed the implication of an N-terminal stretch of ApLyz in the bactericidal function based on the structural mobility of this region. Two N-terminal peptides of ApLyz (residues 1-15 and 1-32), which primarily consist of amphiphilic α-helices, exerted similar bactericidal efficacy and had a strong preference for the Gram-negative strains. Further investigation revealed that the N-terminal peptides are membrane-targeting peptides causing cell permeabilization and also possess nonmembrane disturbing bactericidal mechanism. Overall, in addition to the key findings of novel bactericidal peptides from silkmoth lysozyme, this work laid the foundation for future improvement of ApLyz by protein engineering.
本研究探索了一种来自中国橡树蚕（Antheraea pernyi）的新型溶菌酶 ApLyz，研究其通过 N 端或 C 端融合到酵母细胞表面的活性表达，并评估相应表达的溶菌酶的抗菌活性。ApLyz 的 C 端融合的杀菌活性超过了 N 端融合的杀菌活性，这表明 ApLyz 的 N 端延伸在杀菌功能中具有重要意义，这是基于该区域的结构可移动性。ApLyz 的两个 N 端肽（残基 1-15 和 1-32），主要由两亲性α-螺旋组成，具有相似的杀菌功效，对革兰氏阴性菌有很强的偏好。进一步的研究表明，N 端肽是靶向细胞膜的肽，导致细胞通透性，并具有非膜干扰的杀菌机制。总的来说，除了从蚕溶菌酶中发现新型杀菌肽的关键发现外，这项工作为未来通过蛋白质工程改进 ApLyz 奠定了基础。
