Mechanism of catalysis, E2 recognition, and autoinhibition for the IpaH family of bacterial E3 ubiquitin ligases.

ABSTRACT: IpaH enzymes are secreted bacterial effectors that function within host cells as E3 ubiquitin (Ub) ligases. Catalytic activity is imparted by a conserved novel E3 ligase (NEL) domain that is unique to Gram-negative pathogens and whose activity is repressed by a flanking substrate-binding leucine-rich repeat (LRR) domain when substrate is absent. How the NEL domain catalyzes the conjugation of Ub onto substrates, recognizes host E2s, and maintains its autoinhibited state remain poorly understood. Here we used mutagenesis and enzyme kinetic analyses to address these gaps in knowledge. Mutagenesis of conserved residues on two remote surfaces of the NEL domain identified functional clusters proximal to and distal to the active site cysteine. By analyzing the kinetics of Ub charging and dischar

SUBMITTER: Keszei AF 

PROVIDER: S-EPMC5307447 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature