<p>C-type lysozyme enzymes, such as hen egg white lysozyme (HEWL), provide anti-bacterial activity by cleaving peptidoglycan in Gram-positive bacterial cell walls. In humans, C-type lysozyme is found in all secretions, including tears and saliva. Certain Gram-positive bacteria can produce proteins with anti-lysozyme activity known as Inhibitor of Vertebrate Lysozyme (IVY), which act as virulence factors [<cite idref="PUB00027919"/>, <cite idref="PUB00027883"/>]. IVY proteins have a 3-layer alpha(2)/beta(5)/alpha(2) topology, and contain a protruding 5-residue loop that is essential for their inhibitory effect [<cite idref="PUB00042565"/>].</p>