6CGI

Structure of Salmonella Effector SseK3

Summary for 6CGI

• Entry DOI: 10.2210/pdb6cgi/pdb
• Descriptor: Type III secretion system effector protein, URIDINE-5'-DIPHOSPHATE (3 entities in total)
• Functional Keywords: ssek3, udp-glcnac, glycosyltransferase, arginine-modification, bacterial effectors, transferase, cell invasion
• Biological source: Salmonella typhimurium (strain SL1344)
• Total number of polymer chains: 4
• Total formula weight: 143717.49

Authors

Chung, I.Y.W.,Cygler, M. (deposition date: 2018-02-20, release date: 2018-02-28, Last modification date: 2024-03-13)

Primary citation

Newson, J.P.M.,Scott, N.E.,Yeuk Wah Chung, I.,Wong Fok Lung, T.,Giogha, C.,Gan, J.,Wang, N.,Strugnell, R.A.,Brown, N.F.,Cygler, M.,Pearson, J.S.,Hartland, E.L.
Salmonella Effectors SseK1 and SseK3 Target Death Domain Proteins in the TNF and TRAIL Signaling Pathways.
Mol.Cell Proteomics, 18:1138-1156, 2019

PubMed Abstract: Strains of utilize two distinct type three secretion systems to deliver effector proteins directly into host cells. The effectors SseK1 and SseK3 are arginine glycosyltransferases that modify mammalian death domain containing proteins with -acetyl glucosamine (GlcNAc) when overexpressed ectopically or as recombinant protein fusions. Here, we combined Arg-GlcNAc glycopeptide immunoprecipitation and mass spectrometry to identify host proteins GlcNAcylated by endogenous levels of SseK1 and SseK3 during infection. We observed that SseK1 modified the mammalian signaling protein TRADD, but not FADD as previously reported. Overexpression of SseK1 greatly broadened substrate specificity, whereas ectopic co-expression of SseK1 and TRADD increased the range of modified arginine residues within the death domain of TRADD. In contrast, endogenous levels of SseK3 resulted in modification of the death domains of receptors of the mammalian TNF superfamily, TNFR1 and TRAILR, at residues Arg and Arg respectively. Structural studies on SseK3 showed that the enzyme displays a classic GT-A glycosyltransferase fold and binds UDP-GlcNAc in a narrow and deep cleft with the GlcNAc facing the surface. Together our data suggest that salmonellae carrying and employ the glycosyltransferase effectors to antagonise different components of death receptor signaling.

PubMed: 30902834
DOI: 10.1074/mcp.RA118.001093

Experimental method

X-RAY DIFFRACTION (2.3 Å)