| 摘要: |
| 以含nis Z基因的质粒pHJ201为模板，对乳链菌肽铰链区进行定点突变，并以pMG36e为载体。转入受体菌L．lactis NZ9800进行表达，研究不同电荷铰链区突变体的特性及结构。结果表明，9个突变体中除 N20E nisin Z，M21E nisin Z 和 K22E nisin Z失去抑菌活性外，其余突变体的抑菌活性均有下降；N20K nisin Z 和 M21K nisin Z突变体的抑菌谱发生了变化，其对革兰氏阴性菌沙门氏菌、志贺氏菌和假单胞菌均有抑菌活性。CD谱表明，在波长210～220 nm区，N20K nisin Z 和 M21K nisin Z 的α-helix值均较野生型 nisin Z 略有提高。 |
| 关键词: nis Z 铰链区电荷突变体 定点突变 抑菌谱 |
| DOI： |
| 分类号: |
| 基金项目: |
|
| Inhibition of nisin Z mutants with charge in hinge region |
|
|
| Abstract: |
| To study the effect of charge in hinge region on the relation between structure and function,we changed certain amino acid of hinge region by performing site-directed mutagenesis with nis Z gene.The results showed that the antimicrobial activities of nine mutants decreased,while N20E nisin Z,M21E nisin Z and K22E nisin Z,introducing negative charge residue into hinge region,nearly lost the activity.Compared with wild-type nisin Z,mutant N20K nisin Z and M21K nisin Z displayed antimicrobial activity against gram-negative Shigella,Pseudomonas and Salmonella.Meanwhile,the data of N20K nisin Z and M21K nisin Z CD spectrum showed similarities to that of wild-type nisin Z in secondary structures.The small difference in intensity in the 210-220 nm region between the CD spectra of the wild-type and those of the mutants showed subtle changes in the structural composition of nisin Z. |
| Key words: nis Z the mutants with charge in hinge region site-directed mutagenesis spectra of antibacterial activity |
