Commensal Streptococcus mitis produces two different lipoteichoic acids of type I and type IV
Commensal Streptococcus mitis produces two different lipoteichoic acids of type I and type IV
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DOI：
10.1093/glycob/cwab079
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发表时间：
2021-12-31
期刊：
影响因子：
4.3
通讯作者：
Denapaite, Dalia
中科院分区：
文献类型：
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作者：
Gisch, Nicolas;Peters, Katharina;Denapaite, Dalia
条件致病菌缓症链球菌（Streptococcus mitis）与草绿色链球菌的缓症组的其他成员一样，在其细胞壁中具有含磷酰胆碱（P-Cho）的磷壁酸（TA）。生物信息学分析预测了TA的存在，这些TA与病原体肺炎链球菌中鉴定的TA几乎相同，但对肺炎链球菌的详细分析表明，TA的存在与病原体肺炎链球菌中鉴定的TA几乎相同。迄今为止未进行轻度脂磷壁酸（LTA）。在这里，我们确定了两个S的LTA结构。缓症菌株、高水平β-内酰胺和多重抗生素耐药菌株B6和青霉素敏感菌株NCTC 10712。与生物信息学预测一致，我们发现一种LTA（IV型）的结构类似于肺炎球菌LTA，除了重复单元内葡萄糖部分与半乳糖的交换。进一步的基因组比较表明，大多数S。缓症菌株应含有与S相同的IV型LTA。pneumoniae，提供了一个更完整的理解，这些P-Cho-含有TA的链球菌的缓症组的成员的生物合成。值得注意的是，我们观察到除了IV型LTA，一个额外的聚合物属于LTA类型I在两个调查的S。缓症菌株。该LTA由作为糖脂锚的β-呋喃半乳糖基（1，3）-二酰基甘油和位于呋喃糖苷半乳糖O-6位的聚甘油磷酸链组成。因此，这些细菌能够合成两种不同的LTA聚合物，最有可能通过不同的生物合成途径产生。我们的生物信息学分析揭示了LTA合酶LtaS的流行，最有可能负责第二个LTA版本（I型），在S。缓症链球菌和假乳链球菌菌株。
The opportunistic pathogen Streptococcus mitis possesses, like other members of the Mitis group of viridans streptococci, phosphorylcholine (P-Cho)-containing teichoic acids (TAs) in its cell wall. Bioinformatic analyses predicted the presence of TAs that are almost identical with those identified in the pathogen Streptococcus pneumoniae, but a detailed analysis of S. mitis lipoteichoic acid (LTA) was not performed to date. Here, we determined the structures of LTA from two S. mitis strains, the high-level beta-lactam and multiple antibiotic resistant strain B6 and the penicillin-sensitive strain NCTC10712. In agreement with bioinformatic predictions, we found that the structure of one LTA (type IV) was like pneumococcal LTA, except the exchange of a glucose moiety with a galactose within the repeating units. Further genome comparisons suggested that the majority of S. mitis strains should contain the same type IV LTA as S. pneumoniae, providing a more complete understanding of the biosynthesis of these P-Cho-containing TAs in members of the Mitis group of streptococci. Remarkably, we observed besides type IV LTA, an additional polymer belonging to LTA type I in both investigated S. mitis strains. This LTA consists of ss-galactofuranosyl(1,3)-diacylglycerol as glycolipid anchor and a poly-glycerol-phosphate chain at the O-6 position of the furanosidic galactose. Hence, these bacteria are capable of synthesizing two different LTA polymers, most likely produced by distinct biosynthesis pathways. Our bioinformatics analysis revealed the prevalence of the LTA synthase LtaS, most probably responsible for the second LTA version (type I), among S. mitis and Streptococcus pseudopneumoniae strains.