Sexton DL, Burgold S, Schertel A, Tocheva EI. Super-resolution confocal cryo-CLEM with cryo-FIB milling for
in situ imaging of
Deinococcus radiodurans.
Curr Res Struct Biol 2022;
4:1-9. [PMID:
34977598 PMCID:
PMC8688812 DOI:
10.1016/j.crstbi.2021.12.001]
[Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/17/2021] [Accepted: 12/02/2021] [Indexed: 12/14/2022] Open
Abstract
Studying bacterial cell envelope architecture with electron microscopy is challenging due to the poor preservation of microbial ultrastructure with traditional methods. Here, we established and validated a super-resolution cryo-correlative light and electron microscopy (cryo-CLEM) method, and combined it with cryo-focused ion beam (cryo-FIB) milling and scanning electron microscopy (SEM) volume imaging to structurally characterize the bacterium Deinococcus radiodurans. Subsequent cryo-electron tomography (cryo-ET) revealed an unusual diderm cell envelope architecture with a thick layer of peptidoglycan (PG) between the inner and outer membranes, an additional periplasmic layer, and a proteinaceous surface S-layer. Cells grew in tetrads, and division septa were formed by invagination of the inner membrane (IM), followed by a thick layer of PG. Cytoskeletal filaments, FtsA and FtsZ, were observed at the leading edges of constricting septa. Numerous macromolecular complexes were found associated with the cytoplasmic side of the IM. Altogether, our study revealed several unique ultrastructural features of D. radiodurans cells, opening new lines of investigation into the physiology and evolution of the bacterium.
User-friendly, commercially available method for correlative cryo-super resolution light microscopy (LM) and cryo-FIB-milling.
Cryo-super resolution LM, cryo-FIB milling, cryo-SEM volume imaging, and cryo-electron tomography (cryo-ET) to study Deinococcus radiodurans.
Unique D. radiodurans cell envelope is composed of two membranes, thick peptidoglycan, an additional layer, and an S-layer.
Cytoskeletal filaments FtsA and FtsZ were observed at the leading edges of division septa.
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