Coupling of polymerase and carrier lipid phosphatase prevents product inhibition in peptidoglycan synthesis.
Coupling of polymerase and carrier lipid phosphatase prevents product inhibition in peptidoglycan synthesis.
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DOI：
10.1016/j.tcsw.2018.04.002
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发表时间：
2018-06
期刊：
影响因子：
--
通讯作者：
Vollmer W
中科院分区：
文献类型：
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作者：
Hernández-Rocamora VM;Otten CF;Radkov A;Simorre JP;Breukink E;VanNieuwenhze M;Vollmer W
肽聚糖（PG）是细菌细胞壁的重要组成部分，维持细胞的形状和完整性。PG前体脂质II组装在细胞质膜的内小叶，转移到质周侧，并通过膜锚定的PG合成酶聚合成聚糖链，如A类青霉素结合蛋白（pbp）。PG聚合释放二磷酸形式的载体脂质十一戊烯基焦磷酸（C55-PP）， C55-PP通过膜包埋焦磷酸酶转化为单磷酸形式，生成C55-P，进行新一轮PG前体合成。在这里，我们报道了大肠杆菌中C55-PP焦磷酸酶基因pgpB的缺失增加了对头孢素的敏感性，头孢素是PBP1A特异性的β-内酰胺，这表明pgpB缺失会损害PBP1B的细胞功能。纯化后的PBP1B与PgpB和另一种C55-PP焦磷酸酶、BacA以及两者相互作用，PgpB和BacA刺激PBP1B的糖基转移酶活性。C55-PP被发现是PBP1B的有效抑制剂。我们的数据表明，PgpB对PBP1B的刺激是由于C55-PP的去除和加工速度更快，并且PBP1B在PG合成过程中与C55-PP磷酸酶相互作用，将PG聚合与载体脂质的回收结合起来，防止了C55-PP对产物的抑制。
Peptidoglycan (PG) is an essential component of the bacterial cell wall that maintains the shape and integrity of the cell. The PG precursor lipid II is assembled at the inner leaflet of the cytoplasmic membrane, translocated to the periplasmic side, and polymerized to glycan chains by membrane anchored PG synthases, such as the class A Penicillin-binding proteins (PBPs). Polymerization of PG releases the diphosphate form of the carrier lipid, undecaprenyl pyrophosphate (C55-PP), which is converted to the monophosphate form by membrane-embedded pyrophosphatases, generating C55-P for a new round of PG precursor synthesis. Here we report that deletion of the C55-PP pyrophosphatase gene pgpB in E. coli increases the susceptibility to cefsulodin, a β-lactam specific for PBP1A, indicating that the cellular function of PBP1B is impaired in the absence of PgpB. Purified PBP1B interacted with PgpB and another C55-PP pyrophosphatase, BacA and both, PgpB and BacA stimulated the glycosyltransferase activity of PBP1B. C55-PP was found to be a potent inhibitor of PBP1B. Our data suggest that the stimulation of PBP1B by PgpB is due to the faster removal and processing of C55-PP, and that PBP1B interacts with C55-PP phosphatases during PG synthesis to couple PG polymerization with the recycling of the carrier lipid and prevent product inhibition by C55-PP.