Lactococcin Q, a Novel Two-Peptide Bacteriocin Produced by Lactococcus lactis QU 4
Lactococcin Q, a Novel Two-Peptide Bacteriocin Produced by Lactococcus lactis QU 4
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DOI：
10.1128/aem.72.5.3383-3389.2006
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发表时间：
2006-05
影响因子：
4.4
通讯作者：
T. Zendo;Shoko Koga;Y. Shigeri;J. Nakayama;K. Sonomoto
中科院分区：
文献类型：
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作者：
T. Zendo;Shoko Koga;Y. Shigeri;J. Nakayama;K. Sonomoto
摘要从玉米中分离得到一株产细菌素的乳酸乳球菌（Lactococcus lacactis） QU 4。该细菌素被称为乳球菌素Q，在广泛的革兰氏阳性指示菌株中，仅对乳酸乳杆菌菌株显示抗菌活性。通过丙酮沉淀、阳离子交换层析和反相层析纯化乳球菌蛋白Q。乳球菌蛋白Q由α和β两个肽段组成，其分子质量分别为4,260.43 Da和4,018.36 Da。氨基酸和DNA测序分析表明，乳球菌蛋白Q是一种新型的双肽细菌素，与乳球菌蛋白G同源。用化学合成的乳球菌蛋白Q （Qα + Qβ）和乳球菌蛋白G （Gα + Gβ）进行比较研究表明，混合组合（Qα + Gβ和Gα + Qβ）和原始组合（Qα + Gβ和Gα + Qβ）都具有抗菌活性，尽管每个单肽都没有显著的活性。这四对乳球菌蛋白肽以1:1的摩尔比协同作用，表现出相同的抗菌光谱，但MIC不同。Qα + Gβ的MIC是Qα + Qβ的32倍，表明β肽的差异对抗菌活性的强弱有重要影响。
ABSTRACT A bacteriocin-producing strain, Lactococcus lactis QU 4, was isolated from corn. The bacteriocin, termed lactococcin Q, showed antibacterial activity only against L. lactis strains among a wide range of gram-positive indicator strains tested. Lactococcin Q was purified by acetone precipitation, cation exchange chromatography, and reverse-phase chromatography. Lactococcin Q consisted of two peptides, α and β, whose molecular masses were determined to be 4,260.43 Da and 4,018.36 Da, respectively. Amino acid and DNA sequencing analyses revealed that lactococcin Q was a novel two-peptide bacteriocin, homologous to lactococcin G. Comparative study using chemically synthesized lactococcin Q (Qα plus Qβ) and lactococcin G (Gα plus Gβ) clarified that hybrid combinations (Qα plus Gβ and Gα plus Qβ) as well as original combinations showed antibacterial activity, although each single peptide showed no significant activity. These four pairs of lactococcin peptides acted synergistically at a 1:1 molar ratio and exhibited identical antibacterial spectra but differed in MIC. The MIC of Qα plus Gβ was 32 times higher than that of Qα plus Qβ, suggesting that the difference in β peptides was important for the intensity of antibacterial activity.