Kim Hanbeen, Lee Hyo Gun, Kwon Inhyuk, Seo Jakyeom
Department of Animal Science, Life and Industry Convergence Research Institute, Pusan National University, Miryang 50463, Korea.
EASY BIO, Inc., Seoul 06253, Korea.
Animals (Basel). 2020 Jun 1;10(6):963. doi: 10.3390/ani10060963.
( ) is one of the critical initiators of acute acidosis in ruminants. Therefore, we aimed to develop and characterize the endolysin LyJH307, which can lyse ruminal . We tested the bactericidal activity of recombinant LyJH307 against S. bovis JB1 under a range of pH, temperature, NaCl, and metal ion concentrations. In silico analyses showed that LyJH307 has a modular design with a distinct, enzymatically active domain of the NLPC/P60 superfamily at the N-terminal and a cell wall binding domain of the Zoocin A target recognition domain (Zoocin A_TRD) superfamily at the C-terminal. The lytic activity of LyJH307 against JB1 was the highest at pH 5.5, and relatively higher under acidic, than under alkaline conditions. LyJH307 activity was also the highest at 39 °C, but was maintained between 25°C and 55°C. LyJH307 bactericidal action was retained under 0-500 mM NaCl. While the activity of LyJH307 significantly decreased on treatment with ethylenediaminetetraacetic acid (EDTA), it was only restored with supplementation of 10 mM Ca. Analyses of antimicrobial spectra showed that LyJH307 lysed Lancefield groups D ( group and ) and H ( ) bacteria. Thus, LyJH307 might help to prevent acute ruminal acidosis.
（ ）是反刍动物急性酸中毒的关键引发因素之一。因此，我们旨在开发并表征能裂解瘤胃 的内溶素LyJH307。我们在一系列pH、温度、NaCl和金属离子浓度条件下测试了重组LyJH307对牛链球菌JB1的杀菌活性。计算机分析表明，LyJH307具有模块化设计，在N端有一个NLPC/P60超家族独特的酶活性结构域，在C端有一个动物菌素A靶标识别结构域（动物菌素A_TRD）超家族的细胞壁结合结构域。LyJH307对JB1的裂解活性在pH 5.5时最高，在酸性条件下比在碱性条件下相对更高。LyJH307的活性在39℃时也最高，但在25℃至55℃之间保持稳定。LyJH307在0 - 500 mM NaCl条件下仍保留杀菌作用。虽然用乙二胺四乙酸（EDTA）处理后LyJH307的活性显著降低，但仅补充10 mM Ca时活性才得以恢复。抗菌谱分析表明，LyJH307能裂解兰氏D群（ 群和 ）和H群（ ）细菌。因此，LyJH307可能有助于预防急性瘤胃酸中毒。
