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Publication Abstract from PubMed

Gram-negative pathogens evolved a syringe-like nanomachine, termed type 3 secretion system, to deliver protein effectors into the cytoplasm of host cells. An essential component of this system is a long helical needle filament that protrudes from the bacterial surface and connects the cytoplasms of the bacterium and the eukaryotic cell. Previous structural research was predominantly focused on reconstituted type 3 needle filaments, which lacked the biological context. In this work we introduce a facile procedure to obtain high-resolution cryo-EM structure of needle filaments attached to the basal body of type 3 secretion systems. We validate our approach by solving the structure of Salmonella PrgI filament and demonstrate its utility by obtaining the first high-resolution cryo-EM reconstruction of Shigella MxiH filament. Our work paves the way to systematic structural characterization of attached type 3 needle filaments in the context of mutagenesis studies, protein structural evolution and drug development.

Helical reconstruction of Salmonella and Shigella needle filaments attached to type 3 basal bodies.,Kotov V, Lunelli M, Wald J, Kolbe M, Marlovits TC Biochem Biophys Rep. 2021 Jun 27;27:101039. doi: 10.1016/j.bbrep.2021.101039., eCollection 2021 Sep. PMID:34258394^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.