Distinct and essential morphogenic functions for wall- and lipo-teichoic acids in Bacillus subtilis
Distinct and essential morphogenic functions for wall- and lipo-teichoic acids in Bacillus subtilis
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DOI：
10.1038/emboj.2009.25
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发表时间：
2009-04-08
期刊：
影响因子：
11.4
通讯作者：
Errington, Jeff
中科院分区：
文献类型：
--
作者：
Schirner, Kathrin;Marles-Wright, Jon;Errington, Jeff
磷壁酸（TA）是构成大多数革兰氏阳性细菌细胞壁的主要组分的阴离子聚合物。尽管经过几十年的研究，它们的功能仍然不清楚。TA与细胞壁肽聚糖（壁TA（WTA））或膜（脂质TA（LTA））共价连接。我们对枯草芽孢杆菌LTA合成的关键酶LTA合成酶（LtaS）进行了研究。我们表明，LTA是需要二价阳离子稳态，它的情况下有严重的影响细胞形态和细胞分裂。LTA和WTA的失活都是致命的，对单个突变体的比较表明，它们在伸长（WTA）和分裂（LTA）中具有不同的作用。B。枯草杆菌有四个ltaS旁系同源物，我们展示了它们的作用是如何部分分化的。两个旁系同源物在孢子形成过程中的LTA合成中具有冗余作用，并且它们的缺失在孢子形成中提供了新的绝对阻断。在2.4埃分辨率下解析的LtaS胞质外部分的晶体结构揭示了磷酸化的苏氨酸残基，这提供了有关催化机制的线索并确定了酶的活性位点。
Teichoic acids (TAs) are anionic polymers that constitute a major component of the cell wall in most Gram-positive bacteria. Despite decades of study, their function has remained unclear. TAs are covalently linked either to the cell wall peptidoglycan (wall TA (WTA)) or to the membrane (lipo-TA (LTA)). We have characterized the key enzyme of LTA synthesis in Bacillus subtilis, LTA synthase (LtaS). We show that LTA is needed for divalent cation homoeostasis and that its absence has severe effects on cell morphogenesis and cell division. Inactivation of both LTA and WTA is lethal and comparison of the individual mutants suggests that they have differentiated roles in elongation (WTA) and division (LTA). B. subtilis has four ltaS paralogues and we show how their roles are partially differentiated. Two paralogues have a redundant role in LTA synthesis during sporulation and their absence gives a novel absolute block in sporulation. The crystal structure of the extracytoplasmic part of LtaS, solved at 2.4-angstrom resolution, reveals a phosphorylated threonine residue, which provides clues about the catalytic mechanism and identifies the active site of the enzyme.