Sequence comparisons among HslU proteins from three different biological kingdoms.

<p>(A) Sequence alignment of C-terminal segment and its neighboring region in HslUs from different organisms (See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103027#s2" target="_blank">Materials and Methods</a> for detailed uniprot ID and species). The sequences are grouped in the order prokaryotic, archaeal, eukaryotic HslU1, and eukaryotic HslU2. Shading indicates residues that are identical (bold white in red-shaded box) or highly conserved (red in empty box) between species. Secondary structural elements are indicated above the sequence (α-helix, spring; β-strand, arrow). The mutated residues in this study are marked using a red star and the neighboring residues are marked using blue filled circles at the bottom. The sequence numbers for the aligned residues are also provided. (B) Phylogenetic tree of the aligned HslUs from panel (A). Prokaryotic HslUs are more similar to archael HslUs than to eukaryotic HslUs. There are two eukaryotic HslUs, of which HslU1 is relatively distant from the HslUs in the other kingdoms. The scale bar indicates amino acid substitutions per site.