Sequence alignment and 3D structure of <i>Drosophila</i> crammer.

<p>(<b>A</b>) The multiple sequence alignment of crammer, propeptide-like cysteine protease inhibitors, and human cathepsin propeptides was conducted using the T-coffee algorithm <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054187#pone.0054187-Notredame1" target="_blank">[53]</a> and the on-line server ExPASy (<a href="http://www.uniprot.org/" target="_blank">www.uniprot.org/</a>). Accession numbers of individual sequences appear in parentheses. The identical, conserved, and semi-conserved residues are shaded in black, dark gray, and pale gray, respectively. In the consensus sequence, capital and small letters are used to indicate those residues found in all or most of the sequences, respectively. Residue numbering is based on that of the crammer sequence. DCTSL, propeptide of <i>Drosophila</i> cathepsin L. HCTSL, HCTSK, and HCTSS, propeptides of human cathepsin L, K, and S. (<b>B</b>) 3D structure of crammer shown as a ribbon diagram. The coordinates were taken from the Protein Data Bank (PDB) with the accession code of 2KTW <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054187#pone.0054187-Tseng2" target="_blank">[43]</a>. The mutated residues in this study appear as spheres for the aromatic residues of hydrophobic Cores 1 and 2, and as sticks for the salt bridges. These images were prepared using PyMOL <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054187#pone.0054187-WL1" target="_blank">[54]</a>.