In addition, when tracing the sequence, the RasMol structure does seem to illustrate two large turns just after the first two alpha helices and the three beta-strands. Thus with the exception of the unseen beta strands at the terminal half of the molecule, the MacDNAsis generated secondary structure image and the RasMol image seem to confirm the structure of lysozyme. The five amino acid sequences obtained through the previous Genbank search were analysed for sequence similarity. Recently, sequence analysis has provided another powerful tool for determining evolutionary relationships. Number to the left and right of the sequences and above each sequence group indicate amino acid number.
Black boxes indicate amino acid conservation.
From this figure, it appears that human lysozyme and mouse lysozyme are most closely related. On a more puzzling note, none of the first 35 aa's in the human lysozyme are conserved. Although it is difficult to determine the most primitive sequence, the human lysozyme sequence seems to have mutated significantly from it. Whether there is a function significance or an evolutionary significance to the human protein, is equally difficult to tell, but a sequence comparison on a much larger scale might provide more insight. Proposed Phylogenetic Tree From the sequence alignment produced in Fig. 5, a phylogenetic relationship for lysozyme was constructed.