In vivo analysis of the Escherichia coli ultrastructure by small-angle scattering

IUCrJ

Semeraro, E.F.¹  Forsyth, V.T.²  Porcar, L.²  Devos, J.M.²  Narayanan, T.³ 

[1] ESRF – The European Synchrotron, 38043 Grenoble, France;Institut Laue–Langevin, 38042 Grenoble, France;Life Sciences Department, Keele University, Staffordshire ST5 5BG, England

关键词: IN VIVO ANALYSIS;    ESCHERICHIA COLI;    ULTRASTRUCTURE;    SMALL-ANGLE SCATTERING;   

DOI  :  10.1107/S2052252517013008

学科分类：数学（综合）

来源: International Union of Crystallography

【 摘 要 】

The flagellated Gram-negative bacterium Escherichia coli is one of the most studied microorganisms. Despite extensive studies as a model prokaryotic cell, the ultrastructure of the cell envelope at the nanometre scale has not been fully elucidated. Here, a detailed structural analysis of the bacterium using a combination of small-angle X-ray and neutron scattering (SAXS and SANS, respectively) and ultra-SAXS (USAXS) methods is presented. A multiscale structural model has been derived by incorporating well established concepts in soft-matter science such as a core-shell colloid for the cell body, a multilayer membrane for the cell wall and self-avoiding polymer chains for the flagella. The structure of the cell envelope was resolved by constraining the model by five different contrasts from SAXS, and SANS at three contrast match points and full contrast. This allowed the determination of the membrane electron-density profile and the inter-membrane distances on a quantitative scale. The combination of USAXS and SAXS covers size scales from micrometres down to nanometres, enabling the structural elucidation of cells from the overall geometry down to organelles, thereby providing a powerful method for a non-invasive investigation of the ultrastructure. This approach may be applied for probing in vivo the effect of detergents, antibiotics and antimicrobial peptides on the bacterial cell wall.

【 授权许可】

CC BY