Department of Chemistry, Biotechnology and Food Science, Laboratory of Microbial Gene Technology and Food Microbiology, Norwegian University of Life Sciences, Ås, Norway.
Appl Environ Microbiol. 2012 Jan;78(2):402-10. doi: 10.1128/AEM.06588-11. Epub 2011 Nov 18.
In this work, we purified and characterized a newly identified lantibiotic (salivaricin D) from Streptococcus salivarius 5M6c. Salivaricin D is a 34-amino-acid-residue peptide (3,467.55 Da); the locus of the gene encoding this peptide is a 16.5-kb DNA segment which contains genes encoding the precursor of two lantibiotics, two modification enzymes (dehydratase and cyclase), an ABC transporter, a serine-like protease, immunity proteins (lipoprotein and ABC transporters), a response regulator, and a sensor histidine kinase. The immunity gene (salI) was heterologously expressed in a sensitive indicator and provided significant protection against salivaricin D, confirming its immunity function. Salivaricin D is a naturally trypsin-resistant lantibiotic that is similar to nisin-like lantibiotics. It is a relatively broad-spectrum bacteriocin that inhibits members of many genera of Gram-positive bacteria, including the important human pathogens Streptococcus pyogenes and Streptococcus pneumoniae. Thus, Streptococcus salivarius 5M6c may be a potential biological agent for the control of oronasopharynx-colonizing streptococcal pathogens or may be used as a probiotic bacterium.
在这项工作中，我们从唾液链球菌 5M6c 中纯化并鉴定了一种新发现的类细菌素（唾液菌素 D）。唾液菌素 D 是一种由 34 个氨基酸残基组成的肽（3467.55Da）；编码这种肽的基因座是一个 16.5kb 的 DNA 片段，其中包含编码两种类细菌素前体、两种修饰酶（脱水酶和环化酶）、ABC 转运蛋白、丝氨酸样蛋白酶、免疫蛋白（脂蛋白和 ABC 转运蛋白）、应答调节蛋白和传感器组氨酸激酶的基因。免疫基因（salI）在敏感指示物中异源表达，并对唾液菌素 D 提供了显著的保护作用，证实了其免疫功能。唾液菌素 D 是一种天然的胰蛋白酶抗性类细菌素，与乳链菌肽类似。它是一种相对广谱的细菌素，抑制许多革兰氏阳性菌属的成员，包括重要的人类病原体化脓性链球菌和肺炎链球菌。因此，唾液链球菌 5M6c 可能是控制口腔定植性链球菌病原体的潜在生物制剂，也可能用作益生菌细菌。
