5HKQ

Crystal structure of CDI complex from Escherichia coli STEC_O31

Summary for 5HKQ

• Entry DOI: 10.2210/pdb5hkq/pdb
• Descriptor: Contact-dependent inhibitor A, CdiI immunity protein (3 entities in total)
• Functional Keywords: toxin, antitoxin, structural genomics, psi-biology, midwest center for structural genomics, mcsg, structure-function analysis of polymorphic cdi toxin-immunity protein complexes, uc4cdi, toxin-antitoxin complex, toxin/antitoxin
• Biological source: Escherichia coli; More
• Total number of polymer chains: 2
• Total formula weight: 30939.81

Authors

Michalska, K.,Stols, L.,Eschenfeldt, W.,Goulding, C.W.,Joachimiak, A.,Midwest Center for Structural Genomics (MCSG),Structure-Function Analysis of Polymorphic CDI Toxin-Immunity Protein Complexes (UC4CDI) (deposition date: 2016-01-14, release date: 2017-01-18, Last modification date: 2024-10-23)

Primary citation

Michalska, K.,Quan Nhan, D.,Willett, J.L.E.,Stols, L.M.,Eschenfeldt, W.H.,Jones, A.M.,Nguyen, J.Y.,Koskiniemi, S.,Low, D.A.,Goulding, C.W.,Joachimiak, A.,Hayes, C.S.
Functional plasticity of antibacterial EndoU toxins.
Mol.Microbiol., 109:509-527, 2018

PubMed Abstract: Bacteria use several different secretion systems to deliver toxic EndoU ribonucleases into neighboring cells. Here, we present the first structure of a prokaryotic EndoU toxin in complex with its cognate immunity protein. The contact-dependent growth inhibition toxin CdiA-CT from Escherichia coli STEC_O31 adopts the eukaryotic EndoU fold and shares greatest structural homology with the nuclease domain of coronavirus Nsp15. The toxin contains a canonical His-His-Lys catalytic triad in the same arrangement as eukaryotic EndoU domains, but lacks the uridylate-specific ribonuclease activity that characterizes the superfamily. Comparative sequence analysis indicates that bacterial EndoU domains segregate into at least three major clades based on structural variations in the N-terminal subdomain. Representative EndoU nucleases from clades I and II degrade tRNA molecules with little specificity. In contrast, CdiA-CT and other clade III toxins are specific anticodon nucleases that cleave tRNA between nucleotides C37 and m A38. These findings suggest that the EndoU fold is a versatile scaffold for the evolution of novel substrate specificities. Such functional plasticity may account for the widespread use of EndoU effectors by diverse inter-bacterial toxin delivery systems.

PubMed: 29923643
DOI: 10.1111/mmi.14007

Experimental method

X-RAY DIFFRACTION (2 Å)