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革兰氏阳性菌细胞壁结构获解析
2020-04-30 21:05

英国谢菲尔德大学J. K. Hobbs和S. J. Foster研究团队合作取得一项新成果。他们成功解析了革兰氏阳性菌细胞壁的结构。该项研究成果在线发表在2020年4月29日出版的《自然》上。

研究人员以活细胞和纯化的肽聚糖为底物利用原子力显微镜对形态不同的金黄色葡萄球菌和枯草芽孢杆菌进行了研究。活细胞成熟表面的特征是大孔(直径最大60纳米)、深孔(最大23纳米)构成的肽聚糖无序凝胶。由更多新生成分组成的内部肽聚糖表面要致密得多,聚糖链间距通常小于7 nm。

内表面结构取决于位置。枯草芽孢杆菌的圆柱体具有密集的周向取向;而在金黄色葡萄球菌和分隔隔中,肽聚糖均密集,但方向随机。通过解析分子结构增强了人类对细胞包膜的机械性质和其作为环境界面功能的认知,同时也提供了与传统结构生物学方法互补的信息。

据介绍,细菌细胞壁的主要结构成分是肽聚糖,这对细菌生存至关重要,同时其合成途径也是抗生素的靶点。肽聚糖是由聚糖链组成的单个大分子,该聚糖链通过围绕细胞的肽侧支交联,从而防止内部膨胀。在革兰氏阳性细菌中,肽聚糖的厚度可达数十纳米,通常被认为是为细胞提供机械强度的均匀结构。

附:英文原文

Title: The architecture of the Gram-positive bacterial cell wall

Author: L. Pasquina-Lemonche, J. Burns, R. D. Turner, S. Kumar, R. Tank, N. Mullin, J. S. Wilson, B. Chakrabarti, P. A. Bullough, S. J. Foster, J. K. Hobbs

Issue&Volume: 2020-04-29

Abstract: The primary structural component of the bacterial cell wall is peptidoglycan, which is essential for viability and the synthesis of which is the target for crucial antibiotics1,2. Peptidoglycan is a single macromolecule made of glycan chains crosslinked by peptide side branches that surrounds the cell, acting as a constraint to internal turgor1,3. In Gram-positive bacteria, peptidoglycan is tens of nanometres thick, generally portrayed as a homogeneous structure that provides mechanical strength4,5,6. Here we applied atomic force microscopy7,8,9,10,11,12 to interrogate the morphologically distinct Staphylococcus aureus and Bacillus subtilis species, using live cells and purified peptidoglycan. The mature surface of live cells is characterized by a landscape of large (up to 60 nm in diameter), deep (up to 23 nm) pores constituting a disordered gel of peptidoglycan. The inner peptidoglycan surface, consisting of more nascent material, is much denser, with glycan strand spacing typically less than 7 nm. The inner surface architecture is location dependent; the cylinder of B. subtilis has dense circumferential orientation, while in S. aureus and division septa for both species, peptidoglycan is dense but randomly oriented. Revealing the molecular architecture of the cell envelope frames our understanding of its mechanical properties and role as the environmental interface13,14, providing information complementary to traditional structural biology approaches.

DOI: 10.1038/s41586-020-2236-6

Source: https://www.nature.com/articles/s41586-020-2236-6

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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