Scaffolding of Hepatitis C Virus envelope discontinuous epitopes towards synthetic vaccines

Lobo Ruiz, Ariadna (2016) Scaffolding of Hepatitis C Virus envelope discontinuous epitopes towards synthetic vaccines. MSc(R) thesis, University of Glasgow.

Abstract

It is estimated that in the United States 4 million people are chronically infected with Hepatitis C Virus (HCV).1 The envelope glycoprotein E2 of HCV is the main target for neutralising antibodies, and its structure has been recently elucidated.2,3 A molecular construct mimicking discontinuous epitopes of the neutralising antibodies targeting for E2 arises as a promising prophylactic vaccine against HCV.

Based on the recently elucidated structure of E2 in complex with neutralising antibodies, research was conducted towards the development of potential synthetic vaccines. This project was in collaboration with the MRC-University of Glasgow for Virus Research. A single model peptide suitable for the biological assay was developed, in which the peptide loops were outfitted with a tetraethyelene glycol (TEG) spacer to be the join between the peptides and 96-well maleimide microplates. The best approach for the synthesis of the newly designed TEG spacer was evaluated, and the spacer was conjugated to the peptides by using copper(I)-catalysed click reactions. Several linear peptides were synthesised based on the amino acid sequences of anti-HCV neutralising antibodies' epitopes. These peptides were then cyclised using different linkers in order to improve the solubility of the final cyclic peptides, and finally the newly designed TEG spacer was incorporated. For the preliminary evaluation of the activity of the prepared peptides, a biological assay was developed. Additionally, preliminary fluorescence experiments were performed to evaluate whether the proposed peptide model system was suitable for the ELISA experiments at the required working concentration range.

Conjugation of three peptide loops to the TAC scaffold (TriAzoCyclophane), a symmetric cyclophane ring comprising three secondary amines, turns into a good approach to mimic discontinuous epitopes. Previously in our group, several methodologies for the TAC scaffold functionalization have been established including conjugation via CuAAc reactions or Native Chemical Ligation.4–6 In the current thesis, a novel strategy for the assembly of sulfhydryl-containing molecules on the TAC scaffold was studied. The TAC scaffold was furnished with a bromide functionality, which undergoes nucleophilic attack upon treatment with sulfhydryl-containing molecules. This turns into an efficient manner of incorporating either conformational or linear peptide loops containing a free sulphur moiety.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Keywords: Discontinuous epitopes, synthetic vaccines, peptides, Hepatitis C Virus, chemical biology, bioorganic chemistry.
• Subjects: Q Science > QD Chemistry; Q Science > QH Natural history > QH345 Biochemistry
• Colleges/Schools: College of Science and Engineering > School of Chemistry
• Supervisor's Name: Liskamp, Professor Robert M.J
• Date of Award: 2016
• Embargo Date: 22 February 2020
• Depositing User: Miss Ariadna Lobo Ruiz
• Unique ID: glathesis:2016-7081
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 29 Feb 2016 09:56
• Last Modified: 15 Mar 2016 08:46
• URI: https://theses.gla.ac.uk/id/eprint/7081