Erschienen:
[Erscheinungsort nicht ermittelbar]: Università degli studi di Genova, 2020
Sprache:
Englisch
Identifikator:
Entstehung:
Hochschulschrift:
Dissertation, Università degli studi di Genova, 2020
Anmerkungen:
Beschreibung:
Giant Viruses are a class of uncommon cellular parasites discovered about 30 years ago1. They are defined as Nucleo Cytoplasmic Large DNA viruses (NCLDVs) according to the notable viral particle dimensions (about 400nm) and the genome complexity. In addition, NCLDVs possess genes with cell-like properties", that allow the virus to be, at least in part, independent from the host molecular mechanisms1. One of the most important pathways that is almost totally encoded by NCLDVs is the glycosylation. Generally, viruses use the ER/Golgi compartments of the host to glycosylate their own proteins. For NCLDVs, an almost complete system to elongate, modify and synthetize the glycoforms is set up in the viral factories, which are defined structures in the host cytoplasm. The topic of this work was the study and the characterization of two of the six putative glycosyltransferases (GTs) from Paramecium bursaria Chlorella virus- 1 (PBCV-1): A064R and A075L2. PBCV-1 possesses in fact an highly glycosylated capsid that displays uncommon glycoforms only shared by chloroviruses3. The identification of the glycoform structure suggest that they are probably synthetized by the virus and not by the host. These findings represented the starting point to analyse PBCV-1 genome looking for genes encoding those enzymes. In the present work, A064R is characterized by enzymatic analysis, demonstrating that it is a multidomain enzyme, with two rhamnosyltransferase activities and a methyltransferase one. A075L is also demonstrated to be a GT, by enzymatic analysis and ITC experiments. Experiments aimed also to identify the 3D structure of the protein, and to confirm its interaction with the substrate, the UDP-xylose. The solving of the 3D structure and the enzymatic characterisation are currently underway. A064R and A075L enzymes display interesting catalytic properties that could be explored for biotechnological applications. In fact, the study of the enzymes that process glycans is a recent topic explored for the production of compounds largely used as bioactive molecules 4. Identification of novel GTs will provide new tools that can expand the biological biodiversity of glycans as bioactive natural products, which is well known to participate in the molecules drug efficiency in terms of pharmacokinetics and pharmacodynamics4, and that could be also exploited for the production of new carbohydrate vaccines."