Yamada Arisa, Tamura Haruki, Kato Hirohisa
Department of Dental Pharmacology, School of Dentistry, Iwate Medical University, Morioka, Japan.
FEMS Microbiol Lett. 2009 Feb;291(1):17-23. doi: 10.1111/j.1574-6968.2008.01426.x. Epub 2008 Nov 28.
AtlA is a major cell-lytic enzyme called autolysin in Streptococcus mutans. In this study, we identified the atlg gene-encoding autolysin (Atlg), consisting of 863 residues from Streptococcus sobrinus 6715DP, and confirmed lytic activity of recombinant Atlg by zymography of S. sobrinus cells. An atlA-inactivated mutant was constructed in S. mutans Xc, and the atlg gene product was characterized by plasmid complementation. Microscopic analysis, saliva-induced aggregation assay and autolysis assay of static cultures in air revealed that the atlg gene product partially complemented the role of AtlA. Furthermore, the capability of biofilm formation of the atlA-deficient mutant cultivated in air was restored by plasmid comprising the atlg gene. These findings suggest that Atlg may be involved in cell separation and biofilm formation in S. sobrinus.
AtlA是变形链球菌中一种名为自溶素的主要细胞裂解酶。在本研究中，我们鉴定了来自远缘链球菌6715DP的编码自溶素（Atlg）的atlg基因，其由863个氨基酸残基组成，并通过远缘链球菌细胞的酶谱分析证实了重组Atlg的裂解活性。在变形链球菌Xc中构建了一个atlA失活突变体，并通过质粒互补对atlg基因产物进行了表征。对空气中静态培养物的显微镜分析、唾液诱导聚集试验和自溶试验表明，atlg基因产物部分补充了AtlA的作用。此外，包含atlg基因的质粒恢复了在空气中培养的atlA缺陷突变体形成生物膜的能力。这些发现表明，Atlg可能参与远缘链球菌的细胞分离和生物膜形成。
