Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
Probiotics Antimicrob Proteins. 2018 Jun;10(2):142-147. doi: 10.1007/s12602-017-9374-7.
Genome sequencing of Enterococcus faecium M3K31, a strain isolated from griffon vultures, previously revealed the presence of three sequences encoding for bacteriocins, namely enterocin P, enterocin HF, and a SRCAM 602-like bacteriocin. In this work, we describe the SRCAM 602-like bacteriocin that we named faerocin MK. Mature faerocin MK consists of 43 residues and contains an YGNGV-motif and two cysteine residues at positions 10 and 15, consistent with other class IIa bacteriocins. Faerocin MK and SRCAM 602 were chemically synthesized and their scope of activity was tested. Faerocin MK is active against a wide range of Gram-positive organisms while SRCAM 602 was not active against any tested organism. Although both peptides are more structured in trifluoroethanol, faerocin MK has an α-helical character nearly twice that of SRCAM 602. Nucleotide sequence analysis revealed that the faerocin MK precursor is produced with a 28-amino acid signal peptide and that an immunity gene follows the structural faerocin MK gene. Heterologous expression of the faerocin MK operon showed that faerocin MK and its immunity protein were successfully expressed in other organisms. This indicates that the bacteriocin is secreted through the sec pathway.
从秃鹫中分离出的屎肠球菌 M3K31 的基因组测序显示，该菌株存在三个编码细菌素的序列，分别为肠球菌素 P、肠球菌素 HF 和一种 SRCAM 602 样细菌素。在这项工作中，我们描述了一种我们命名为 faerocin MK 的 SRCAM 602 样细菌素。成熟的 faerocin MK 由 43 个残基组成，包含一个 YGNGV 基序和两个半胱氨酸残基，分别位于第 10 位和第 15 位，与其他 IIa 类细菌素一致。faerocin MK 和 SRCAM 602 被化学合成，并测试了它们的活性范围。faerocin MK 对广泛的革兰氏阳性菌具有活性，而 SRCAM 602 对任何测试的菌均无活性。尽管这两种肽在三氟乙醇中都具有更多的结构，但 faerocin MK 的α-螺旋特征几乎是 SRCAM 602 的两倍。核苷酸序列分析表明，faerocin MK 的前体带有一个 28 个氨基酸的信号肽，并且在结构 faerocin MK 基因之后有一个免疫基因。faerocin MK 操纵子的异源表达表明，faerocin MK 和其免疫蛋白在其他生物体中成功表达。这表明细菌素通过 sec 途径分泌。
