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Structural characterization of the Helicobacter pylori Cag T4SS using single particle cryo-EM


EMSL Project ID
51298

Abstract

Using cryo-EM we determined the structure of the 5.6 MDa H. pylori Cag T4SS at a resolution of ~3.6 Å. The Hp T4SS is structurally different from T4SS structures seen in other species and has an unexpected symmetry mismatch between the 14-fold outer membrane core complex (OMCC) and a contiguous 17-fold periplasmic ring complex (PRC). There are no crystal structures of the individual T4SS components and the 3.6 Å resolution did not allow us to build the entire model de novo. We are requesting Titan microscope time at the national center because the University of Michigan cryo-EM facility is closed for construction from December 2019 until June 2020. Our goal is to collect the data required to push the resolution of the complex to sub-3.0 Å, allowing us to build models of all the T4SS components. We have grids that are screened and ready for imaging in the Titan Krios.

Project Details

Start Date
2020-03-15
End Date
2021-03-17
Status
Closed

Team

Principal Investigator

Melanie Ohi
Institution
University of Michigan

Team Members

Jeong Min Chung
Institution
University of Michigan

Clarissa Durie
Institution
University of Michigan

Nancy Meyer
Institution
Oregon Health & Science University