In ovoid-shaped, Gram-positive bacteria, MapZ guides FtsZ-ring positioning at cell equators. The cell wall of the ovococcus Streptococcus mutans contains peptidoglycan decorated with serotype c carbohydrates (SCCs). In the present study, we identify the major cell separation autolysin AtlA as an SCC-binding protein. AtlA binding to SCC is attenuated by the glycerol phosphate (GroP) modification. Using fluorescently labeled AtlA constructs, we mapped SCC distribution on the streptococcal surface, revealing enrichment of GroP-deficient immature SCCs at the cell poles and equators. The immature SCCs co-localize with MapZ at the equatorial rings throughout the cell cycle. In GroP-deficient mutants, AtlA is mislocalized, resulting in dysregulated cellular autolysis. These mutants display morphological abnormalities associated with MapZ mislocalization, leading to FtsZ-ring misplacement. Altogether, our data support a model in which maturation of a cell wall polysaccharide provides the molecular cues for the recruitment of cell division machinery, ensuring proper daughter cell separation and FtsZ-ring positioning.

在卵形的革兰氏阳性细菌中，MapZ 引导 FtsZ 环定位在细胞赤道。ovococcus Streptococcus mutans 的细胞壁含有装饰有血清型c的肽聚糖碳水化合物（SCC）。在本研究中，我们将主要的细胞分离自溶素 AtlA 确定为 SCC 结合蛋白。AtlA 与 SCC 的结合因磷酸甘油 (GroP) 修饰而减弱。使用荧光标记的 AtlA 构建体，我们绘制了链球菌表面上的 SCC 分布图，揭示了 GroP 缺陷型未成熟 SCC 在细胞两极和赤道的富集。在整个细胞周期中，未成熟的 SCC 与 MapZ 共同定位于赤道环。在 GroP 缺陷突变体中，AtlA 定位错误，导致细胞自溶失调。这些突变体显示与 MapZ 错误定位相关的形态异常，导致 FtsZ 环错位。共，