The atlA operon of Streptococcus mutans:: Role in autolysin maturation and cell surface biogenesis
The atlA operon of Streptococcus mutans:: Role in autolysin maturation and cell surface biogenesis
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DOI：
10.1128/jb.00536-06
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发表时间：
2006-10-01
影响因子：
3.2
通讯作者：
Burne, Robert A.
中科院分区：
文献类型：
--
作者：
Ahn, Sang-Joon;Burne, Robert A.
Smu0630蛋白(ATLA)最近被发现参与细胞分离、生物膜形成和自溶。在这里，转录研究表明，ATLA是至少受三个启动子控制的多基因操纵子的一部分。在培养基中加入纯化的ATLA蛋白，可使非极性突变株的形态和生物膜形成能力恢复到野生型菌株。一系列ATLA的截短衍生物表明，完整的活性需要C末端和重复区域。ATLA是与细胞相关的，很容易用十二烷基硫酸钠从其中提取。特别有趣的是，与野生型菌株相比，ATLA缺陷菌株的表面蛋白图谱发生了显著变化，多功能粘附素P1与细胞壁的关联也是如此。此外，缺乏ATLA的菌株未能像亲本菌株那样有效地发展竞争能力。THMA的突变可以与ATLA共转录，并编码一种可能的成孔蛋白，导致了与ATLA缺陷株非常相似的表型。THMA也被证明是有效地将ATLA加工成成熟型所必需的，而用全长ATLA蛋白处理THMA突变株并不能恢复正常的细胞分离和生物膜的形成。操纵子中其他基因的突变对细胞分裂、生物膜形成或ATLA生物发生的影响并不是那么深刻。这项研究表明，ATLA是一种表面相关蛋白，在连接细胞表面生物发生、生物膜形成、遗传能力和自溶的网络中发挥着关键作用。
The Smu0630 protein (AtlA) was recently shown to be involved in cell separation, biofilm formation, and autolysis. Here, transcriptional studies revealed that atlA is part of a multigene operon under the control of at least three promoters. The morphology and biofilm-forming capacity of a nonpolar altA mutant could be restored to that of the wild-type strain by adding purified AtlA protein to the medium. A series of truncated derivatives of AtlA revealed that full activity required the C terminus and repeat regions. AtlA was cell associated and readily extractable from with sodium dodecyl sulfate. Of particular interest, the surface protein profile of AtlA-deficient strains was dramatically altered compared to the wild-type strain, as was the nature of the association of the multifunctional adhesin P1 with the cell wall. In addition, AtlA-deficient strains failed to develop competence as effectively as the parental strain. Mutation of thmA, which can be cotranscribed with atlA and encodes a putative pore-forming protein, resulted in a phenotype very similar to that of the AtlA-deficient strain. ThmA was also shown to be required for efficient processing of AtlA to its mature form, and treatment of the thmA mutant strain with full-length AtlA protein did not restore normal cell separation and biofilm formation. The effects of mutating other genes in the operon on cell division, biofilm formation, or AtlA biogenesis were not as profound. This study reveals that AtlA is a surface-associated protein that plays a critical role in the network connecting cell surface biogenesis, biofilm formation, genetic competence, and autolysis.