Molecular design of lysozyme for switching the antimicrobial action

为了扩大其对革兰氏阴性菌和革兰氏阳性菌的抑菌作用，对蛋清溶菌酶进行了基因改造的分子设计。五疏水肽（ph - ph - val - ala - pro）融合到溶菌酶的C端。所得肽融合溶菌酶（H5-Lz）对革兰氏阴性菌和阳性菌均有较强的杀菌作用。H5-Lz在毕赤酵母表达体系中分泌量显著增加，而在酵母菌中分泌量很低。酵母。H5-Lz的构象保持折叠形式，但稳定性略有下降，反映了疏水肽的融合。H5-Lz可用于工业应用。典型的例子是H5-Lz通过农杆菌侵染进入烟叶。转基因烟草对灰霉病和白粉病具有较强的抗性。

In order to expand the antimicrobial action to Gram-negative and Gram-positive, the molecular design of hen egg white lysozyme was attempted by genetic modification. The penta hydrophobic peptide (Phe-Phe-Val-Ala-Pro) was fused to the C terminus of lysozyme. The resulting petapeptide fused lysozyme (H5-Lz) showed strong bactericidal action against Gram-negative and -positive bacteria. The secretion amount of H5-Lz greatly increased in Pichia pastoris expression system, although it was very poor in Saccharomyces . cerevisiae. The conformation of H5-Lz was kept in a folded form, but the stability was lightly decreased, reflecting the fusion of hydrophobic peptide. The H5-Lz can be useful for industrial applications. As a typical example, the H5-Lz was introduce into tobacco leaf through agrobacterium infection. The transgenic tobacco showed strong resistance to gray mold and powdery mildew infection.