Department of Microbiology Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
Microb Biotechnol. 2012 Jul;5(4):501-8. doi: 10.1111/j.1751-7915.2011.00324.x. Epub 2012 Jan 20.
Nisin A is the best known and most extensively characterized lantibiotic. As it is ribosomally synthesized, bioengineering-based strategies can be used to generate variants. We have previously demonstrated that bioengineering of the hinge region of nisin A can result in the generation of variants with enhanced anti-microbial activity against Gram-positive pathogens. Here we created a larger bank of hinge variant producers and screened for producers that exhibit enhanced bioactivity as assessed by agar-based assays against a selection of target strains. Further analysis of 12 'lead' variants reveals that in many cases enhanced bioactivity is not attributable to enhanced specific activity but is instead as a consequence of an enhanced ability to diffuse through complex polymers. In the case of two variants, which contain the residues SVA and NAK, respectively, within the hinge region, we demonstrate that this enhanced trait enables the peptides to dramatically outperform nisin A with respect to controlling Listeria monocytogenes in commercially produced chocolate milk that contains carrageenan as a stabilizer.
乳链菌肽 A 是研究最为透彻、应用最为广泛的细菌素。因其为核糖体合成，因此可以通过基因工程手段对其进行改造，从而产生变体。我们之前已经证明，通过对乳链菌肽 A 的铰链区域进行生物工程改造，可以产生对革兰氏阳性病原体具有增强抗菌活性的变体。在这里，我们创建了一个更大的铰链变体产生库，并通过琼脂基础测定筛选出对一系列靶标菌株表现出增强生物活性的变体。对 12 种“先导”变体的进一步分析表明，在许多情况下，增强的生物活性不是归因于增强的比活度，而是由于增强了通过复杂聚合物扩散的能力。在两种变体的情况下，分别在铰链区域内含有 SVA 和 NAK 残基，我们证明这种增强的特性使这些肽在控制含有卡拉胶作为稳定剂的商业生产巧克力牛奶中的单核细胞增生李斯特菌方面，能够显著优于乳链菌肽 A。
