5J43

CdiA-CT from uropathogenic Escherichia coli in complex with CysK

DOI: 10.2210/pdb5J43/pdb

Classification: TOXIN
Organism(s): Escherichia coli O157:H7, Escherichia coli 536
Expression System: Escherichia coli BL21(DE3)
Mutation(s): Yes

Deposited: 2016-03-31 Released: 2016-07-27
Deposition Author(s): Morse, R.P., Goulding, C.W., Johnson, P.M.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 2.70 Å
R-Value Free: 0.224
R-Value Work: 0.200
R-Value Observed: 0.202

wwPDB Validation 3D Report Full Report

This is version 1.2 of the entry. See complete history.

Literature

Unraveling the essential role of CysK in CDI toxin activation.

Johnson, P.M., Beck, C.M., Morse, R.P., Garza-Sanchez, F., Low, D.A., Hayes, C.S., Goulding, C.W.

(2016) Proc Natl Acad Sci U S A 113: 9792-9797

PubMed: 27531961 Search on PubMedSearch on PubMed Central
DOI: 10.1073/pnas.1607112113
Primary Citation of Related Structures:
5J43, 5J5V

PubMed Abstract:

Contact-dependent growth inhibition (CDI) is a widespread mechanism of bacterial competition. CDI(+) bacteria deliver the toxic C-terminal region of contact-dependent inhibition A proteins (CdiA-CT) into neighboring target bacteria and produce CDI immunity proteins (CdiI) to protect against self-inhibition. The CdiA-CT(EC536) deployed by uropathogenic Escherichia coli 536 (EC536) is a bacterial toxin 28 (Ntox28) domain that only exhibits ribonuclease activity when bound to the cysteine biosynthetic enzyme O-acetylserine sulfhydrylase A (CysK). Here, we present crystal structures of the CysK/CdiA-CT(EC536) binary complex and the neutralized ternary complex of CysK/CdiA-CT/CdiI(EC536) CdiA-CT(EC536) inserts its C-terminal Gly-Tyr-Gly-Ile peptide tail into the active-site cleft of CysK to anchor the interaction. Remarkably, E. coli serine O-acetyltransferase uses a similar Gly-Asp-Gly-Ile motif to form the "cysteine synthase" complex with CysK. The cysteine synthase complex is found throughout bacteria, protozoa, and plants, indicating that CdiA-CT(EC536) exploits a highly conserved protein-protein interaction to promote its toxicity. CysK significantly increases CdiA-CT(EC536) thermostability and is required for toxin interaction with tRNA substrates. These observations suggest that CysK stabilizes the toxin fold, thereby organizing the nuclease active site for substrate recognition and catalysis. By contrast, Ntox28 domains from Gram-positive bacteria lack C-terminal Gly-Tyr-Gly-Ile motifs, suggesting that they do not interact with CysK. We show that the Ntox28 domain from Ruminococcus lactaris is significantly more thermostable than CdiA-CT(EC536), and its intrinsic tRNA-binding properties support CysK-independent nuclease activity. The striking differences between related Ntox28 domains suggest that CDI toxins may be under evolutionary pressure to maintain low global stability.

Organizational Affiliation:

Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697; Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697 celia.goulding@uci.edu christopher.hayes@lifesci.ucsb.edu.

Macromolecules

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cysteine synthase A	A, E	323	Escherichia coli O157:H7	Mutation(s): 0 Gene Names: cysK, Z3680, ECs3286 EC: 2.5.1.47 (PDB Primary Data), 4.5.1.5 (UniProt)
Find proteins for P0ABK5 (Escherichia coli (strain K12)) Explore P0ABK5 Go to UniProtKB: P0ABK5
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Reference Sequence

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
tRNA nuclease CdiA	B, F	239	Escherichia coli 536	Mutation(s): 1 Gene Names: cdiA, ECP_4580 EC: 3.1
Find proteins for Q0T963 (Escherichia coli O6:K15:H31 (strain 536 / UPEC)) Explore Q0T963 Go to UniProtKB: Q0T963
Protein Feature View Expand
Reference Sequence