3ckd

Publication Abstract from PubMed

IpaH proteins are E3 ubiquitin ligases delivered by the type III secretion apparatus into host cells upon infection of humans by the Gram-negative pathogen Shigella flexneri. These proteins comprise a variable leucine-rich repeat-containing N-terminal domain and a conserved C-terminal domain harboring an invariant cysteine residue that is crucial for activity. IpaH homologs are encoded by diverse animal and plant pathogens. Here we demonstrate that the IpaH C-terminal domain carries the catalytic activity for ubiquitin transfer and that the N-terminal domain carries the substrate specificity. The structure of the IpaH C-terminal domain, determined to 2.65-A resolution, represents an all-helical fold bearing no resemblance to previously defined E3 ubiquitin ligases. The conserved and essential cysteine residue lies on a flexible, surface-exposed loop surrounded by conserved acidic residues, two of which are crucial for IpaH activity.

Structure of the Shigella T3SS effector IpaH defines a new class of E3 ubiquitin ligases.,Singer AU, Rohde JR, Lam R, Skarina T, Kagan O, Dileo R, Chirgadze NY, Cuff ME, Joachimiak A, Tyers M, Sansonetti PJ, Parsot C, Savchenko A Nat Struct Mol Biol. 2008 Dec;15(12):1293-301. Epub 2008 Nov 9. PMID:18997778^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.