Figure 2.

Structure of RavZ. (A) Ribbon diagram of RavZ from L. pneumophila. The catalytic (residues 49–325) and membrane targeting (residues 326–423) domains are colored aquamarine and yellow, respectively. The catalytic site is indicated by an arrow. The N-terminal 48 and C-terminal 71 residues are missing and shown as red and green dots, respectively. The secondary structural elements are labeled sequentially. (B) Schematic representation of full-length RavZ. The invisible N-terminal and C-terminal regions in the crystal structure are represented by a red and green dotted line, respectively. The putative LC3-binding sites, LIR1, LIR2 and LIR3, are marked. (C) Superposition of 2 crystal structures (crystal form I and III) showing different loop conformations near the active site. This view is re-oriented from Fig. 2A to show the catalytic triad (approximately 110° and 30° along the horizontal and vertical axes, respectively). The overall structure is virtually identical except for the active site region. (D) A close-up view of the active site, which is highlighted as a transparent box in panel (C). The active site is covered by the flexible internal loop in the closed conformation of crystal form I (cyan), whereas it is widely accessible in the open conformation of crystal form III (blue). Catalytic triad residues (His176, Asp197 and Cys258) are presented as stick models. The interacting atoms in the catalytic triad are lined green and yellow for the closed and open conformations, respectively. The movement of the flexible loop is indicated by a double-headed red arrow.