FIG 3.

Structural mapping of insertions and deletions observed in characterized HipA kinases. (A) Schematic overview of HipA showing the conserved regions (the Gly-rich loop, activation loop, catalytic motif, and Mg-binding motif) in red as well as insertions (ω [green]) and deletions (Δ [blue]) in C. crescentus HipA₁ and HipA₂ relative to HipA from E. coli K-12 based the sequence alignment shown in Fig. S3. An insertion in HipA₁ relative to HipA is denoted ω5′, while insertions in HipA₂ relative to HipA are marked ω1″, ω2″, ω3″, ω4″, and ω6″. Deletions in HipA₁ and HipA₂ relative to HipA are marked Δ1, Δ2, and Δ3. Regions of high sequence divergence are shown in yellow. (B) Mapping of the insertions and deletions in HipA₁ onto the structure of HipA of E. coli K-12 (PDB accession no. 3FBR) using the same nomenclature and color scheme as in panel A (45). ATP is shown with colored sticks. (C) Mapping of the insertions and deletions in HipA₂ onto the structure of HipA. Note that the insertions ω1″ and ω3″ in HipA₂ are located close to the region that in HipA interacts with the C terminus of HipB (yellow sticks) and could perhaps affect antitoxin activity.