Peptidoglycan precursor synthesis along the sidewall of pole-growing mycobacteria
Peptidoglycan precursor synthesis along the sidewall of pole-growing mycobacteria
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DOI：
10.7554/elife.37243
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发表时间：
2018-09-10
期刊：
影响因子：
7.7
通讯作者：
Siegrist, M. Sloan
中科院分区：
文献类型：
--
作者：
Garcia-Heredia, Alam;Pohane, Amol Arunrao;Siegrist, M. Sloan
杆状分枝杆菌从它们的两极扩张，然而D-氨基酸探针标记该属在两极和侧壁的细胞壁肽聚糖。我们试图澄清这些探针的代谢命运。单肽掺入减少抗生素，阻断肽聚糖合成或L，D-转肽和L，D-转肽酶突变体。二肽补充D-丙氨酸合成或连接中的缺陷，并且存在于脂质连接的肽聚糖前体中。表征探针摄取途径，使我们能够定位肽聚糖代谢的精度：二肽标记的L，D-转肽酶重塑和二肽标记的合成是一致的，在两极，隔膜和侧壁的菌膜代谢。荧光青霉素标记的D，D-转肽细胞周边周围进一步表明，分枝杆菌侧壁是一个网站的细胞壁组装。虽然极性肽聚糖的合成与细胞伸长，侧壁合成细胞壁损伤。肽聚糖编辑沿着侧壁可支持极生长分枝杆菌中的细胞壁稳健性。
Rod-shaped mycobacteria expand from their poles, yet D-amino acid probes label cell wall peptidoglycan in this genus at both the poles and sidewall. We sought to clarify the metabolic fates of these probes. Monopeptide incorporation was decreased by antibiotics that block peptidoglycan synthesis or L,D-transpeptidation and in an L,D-transpeptidase mutant. Dipeptides complemented defects in D-alanine synthesis or ligation and were present in lipid-linked peptidoglycan precursors. Characterizing probe uptake pathways allowed us to localize peptidoglycan metabolism with precision: monopeptide-marked L,D-transpeptidase remodeling and dipeptide-marked synthesis were coincident with mycomembrane metabolism at the poles, septum and sidewall. Fluorescent pencillin-marked D,D-transpeptidation around the cell perimeter further suggested that the mycobacterial sidewall is a site of cell wall assembly. While polar peptidoglycan synthesis was associated with cell elongation, sidewall synthesis responded to cell wall damage. Peptidoglycan editing along the sidewall may support cell wall robustness in pole-growing mycobacteria.