<p>(A) Structural alignment of two VicK DHp chains; (B) The VicK DHp domain aligned with <i>T. maritima</i> HK853. The HK853 DHp domain is colored in blue. VicK His217 and Pro222 are indicated with arrows. Bottom parts of helices (aa219–255) of the VicK DHp domain were used for alignments. The right is a top view of these aligned structures shown on the left. The blue arrows indicate direction and relative distance of shifts. The red circle represents a central axis parallel to the DHp domain and going into the paper. (C) Conservation and helicity of the DHp domain. The bottom part is a conservation logo using over 40 non-redundant histidine kinases. The top part is the helicity of the DHp domain calculated by Phyre described in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001493#s4" target="_blank">Materials and Methods</a>. (D) Autokinase analysis using isotope γ<sup>32</sup>P-ATP. The wt VicK and its mutants were analyzed on 15% SDS-PAGE and stained with coomassie blue as shown in the bottom gel. The top gel is an autoradiograph of their autokinase activities of these proteins. A protein marker served as a background control (lane 3).</p
