Protein-oligosaccharide interaction mechanisms in chitinases engineered towards neolectins

Speciſc protein-carbohydrate interactions are fundamental to many biomolecular recognition events. The study concentrates on fungal 42kDa chitinase from Trichoderma harzianum, a naturally chitin (polymer of N-acetylglucosamine residues) degrading enzyme. It has shown activity also on synthetically modiſed D-1,3- fucosylated and E-1,4-galactosylated, more animal type of chitooligosaccharides. The structure of chitinase (D/E-barrel fold) with the substrate binding cleft formed by limited number of loops provides an excellent platform for directed evolution studies. In this study our aim is to obtain atomic level understanding of the factors determining the interactions between an oligosaccharide and a protein by using molecular dynamic simulations. The results from modeling are compared with the experimental data (mutagenesis, mass spectroscopy and nuclear magnetic resonance). The computational studies with the experimental work aim at development of neolectins, i.e. proteins selectively binding to given, medically important, oligosaccharide structures, achieved by ſrst deactivating and then engineering fungal chitinases towards the desired speciſcity and afſnity.