Characterization of O-Acetylation of N-Acetylglucosamine A NOVEL STRUCTURAL VARIATION OF BACTERIAL PEPTIDOGLYCAN
Characterization of O-Acetylation of N-Acetylglucosamine A NOVEL STRUCTURAL VARIATION OF BACTERIAL PEPTIDOGLYCAN
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DOI：
10.1074/jbc.m111.241414
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发表时间：
2011-07-08
影响因子：
4.8
通讯作者：
Chapot-Chartier, Marie-Pierre
中科院分区：
文献类型：
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作者：
Bernard, Elvis;Rolain, Thomas;Chapot-Chartier, Marie-Pierre
肽聚糖 (PG) N-乙酰胞壁酸 (MurNAc) O-乙酰化广泛存在于革兰氏阳性菌中，通常与对溶菌酶和内源性自溶素的耐药性相关。我们在此报告了植物乳杆菌 PG 中 N-乙酰氨基葡萄糖 (GlcNAc) 上存在 O-乙酰化。细菌中从未描述过这种聚糖链的修饰。对植物乳杆菌 PG 释放的乙酰化 Muropeptides 的精细结构表征表明，该物种中的 MurNAc 和 GlcNAc 都是 O-乙酰化的。这两个 PG 后修饰依赖于两个专用的 O-乙酰转移酶编码基因，分别命名为 oatA 和 oatB。通过分析突变菌株对细胞壁水解的抵抗力，我们发现 GlcNAc O-乙酰化会抑制 N-乙酰氨基葡萄糖苷酶 Acm2（植物乳杆菌的主要自溶素）。在该细菌物种中，编码 MurNAc O-乙酰转移酶的 oatA 失活导致对溶菌酶显着敏感。此外，MurNAc 过-O-乙酰化被证明可以通过推定的 N-乙酰胞壁酰-L-丙氨酸酰胺酶 LytH 激活自溶。我们的数据表明，在植物乳杆菌中，两种不同的O-乙酰转移酶在内源性自溶素活性的调节中发挥着原始和拮抗的作用。
Peptidoglycan (PG) N-acetyl muramic acid (MurNAc) O-acetylation is widely spread in Gram-positive bacteria and is generally associated with resistance against lysozyme and endogenous autolysins. We report here the presence of O-acetylation on N-acetylglucosamine (GlcNAc) in Lactobacillus plantarum PG. This modification of glycan strands was never described in bacteria. Fine structural characterization of acetylated muropeptides released from L. plantarum PG demonstrated that both MurNAc and GlcNAc are O-acetylated in this species. These two PG post-modifications rely on two dedicated O-acetyltransferase encoding genes, named oatA and oatB, respectively. By analyzing the resistance to cell wall hydrolysis of mutant strains, we showed that GlcNAc O-acetylation inhibits N-acetylglucosaminidase Acm2, the major L. plantarum autolysin. In this bacterial species, inactivation of oatA, encoding MurNAc O-acetyltransferase, resulted in marked sensitivity to lysozyme. Moreover, MurNAc over-O-acetylation was shown to activate autolysis through the putative N-acetylmuramoyl-L-alanine amidase LytH enzyme. Our data indicate that in L. plantarum, two different O-acetyltransferases play original and antagonistic roles in the modulation of the activity of endogenous autolysins.