7UBZ image
Entry Detail
PDB ID:
7UBZ
Title:
Chymotrypsin digested toxin/immunity complex for a T6SS lipase effector from E. cloacae
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2022-03-15
Release Date:
2022-08-24
Method Details:
Experimental Method:
Resolution:
1.75 Å
R-Value Free:
0.18
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Ankyrin repeat domain-containing protein
Chain IDs:A, B (auth: C)
Chain Length:230
Number of Molecules:2
Biological Source:Enterobacter cloacae
Polymer Type:polypeptide(L)
Description:T6SS lipase effector
Chain IDs:C (auth: B), D
Chain Length:313
Number of Molecules:2
Biological Source:Enterobacter cloacae
Primary Citation
Advanced glycation end-product crosslinking activates a type VI secretion system phospholipase effector protein.
Nat Commun 15 8804 8804 (2024)
PMID: 39394186 DOI: 10.1038/s41467-024-53075-x

Abstact

Advanced glycation end-products (AGE) are a pervasive form of protein damage implicated in the pathogenesis of neurodegenerative disease, atherosclerosis and diabetes mellitus. Glycation is typically mediated by reactive dicarbonyl compounds that accumulate in all cells as toxic byproducts of glucose metabolism. Here, we show that AGE crosslinking is harnessed to activate an antibacterial phospholipase effector protein deployed by the type VI secretion system of Enterobacter cloacae. Endogenous methylglyoxal reacts with a specific arginine-lysine pair to tether the N- and C-terminal α-helices of the phospholipase domain. Substitutions at these positions abrogate both crosslinking and toxic phospholipase activity, but in vitro enzyme function can be restored with an engineered disulfide that covalently links the N- and C-termini. Thus, AGE crosslinking serves as a bona fide post-translation modification to stabilize phospholipase structure. Given the ubiquity of methylglyoxal in prokaryotic and eukaryotic cells, these findings suggest that glycation may be exploited more generally to stabilize other proteins. This alternative strategy to fortify tertiary structure could be particularly advantageous in the cytoplasm, where redox potentials preclude disulfide bond formation.

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