Structural insight into the membrane targeting domain of the Legionella deAMPylase SidD
Fig 5
The carboxy-terminal helix bundle determines localization specificity.
(A) Schematic representation of CTD and its variants. Numbers indicate amino acid positions; asterisks represent residues altered by site-directed mutagenesis. The hydrophobic loop is shown in grey, and the region required for specific localization of CTD to Golgi membranes is highlighted in green. The intracellular localization of each CTD mutant (as shown in (C)) is summarized on the right. (B) Ribbon diagram of SidD-CTD (aa 322–450) colored in orange and the C-terminal helix-turn-helix bundle is colored in green. The relative position of the deAMPylation domain is shown in transparent slate. (C) Intracellular localization of CTD variants. Transiently transfected COS-1 cells producing the indicated GFP-CTD proteins (left) were chemically fixed and stained for giantin (middle). The localization of SidD relative to giantin is shown on the right. Scale bar, 10 μm. (D) Localization of CTD(322–450) to mitochondria membranes. Transiently transfected COS-1 cells coproducing GFP-CTD(322–450) or GFP-CTD(322–450; F370S) and Mito-RFP (a mitochondria marker) were chemically fixed, and the fluorescence signal was examined by confocal microscopy. Arrowheads indicate the position of membranes magnified in the insets. Scale bar, 10 μm.