Transglutaminases are well-known mammalian enzymes, although they are rare or absent in fungi. But in Candida, the researchers found a protein that also bound to transglutaminase. We wondered why Candida would have a substrate protein for these mammalian enzymes, Sundstrom said. We re talking about a fungal protein that is a substrate for a mammalian enzyme. This enzyme is special since it can cross-link proteins together, two different proteins.
Most enzymes don t do that.
This type of covalent adhesion has not been described previously in any viruses, bacteria, fungi or other microorganisms. Several years ago, S.D. Bradway, a former assistant professor of periodontology at Ohio State and co-author on this paper, showed that Candida albicans could form stable attachments. However, that work did not identify what proteins were involved. Sundstrom s group used a strain of Candida in which the transglutaminase-binding protein had been removed and tested its ability to adhere to human oral mucosal cells. Without the protein, there was a five-fold reduction in the ability of Candida to attach.