Amino acid sequence alignment of the two types of N. khasiana basic endochitinases, NkCHIT1b-1 and NkCHIT2b-1. Identical residues are shown in black. The putative leader peptide is marked by a continuous line above it, the cysteine-rich domain by a broken line above it, the proline-rich region by asterisks, and the C-terminal extension by crosses. Vertical arrows pointing upward mark the six amino acid residues differing between NkCHIT2b-1 and NkCHIT2b-2. Predicted glycosylation sites (ExPASy—Biochemical Pathways) are marked by open triangles. Residues suggested to be of functional importance are marked above the sequence by the following symbols: cysteines—involved in disulphide bridges (open circles), glutamic acid and asparagine—important for enzymatic catalysis (filled circles), threonine and glutamine—involved in maintenance of active site geometry (open squares), tyrosine—suggested to affect substrate binding in the catalytic cleft (filled square).