Structural and Functional Characterisation of the Dengue Virus NS4B Protein as a Therapeutic Target in West African Dengue Strains

Dengue virus non-structural protein 4B (NS4B) is a key component of the viral replication complex and an emerging antiviral target that has not been characterised in dengue strains circulating in West Africa, where Dengue virus serotypes 1, 2, and 3 are predominantly co-circulating. Structural differences between Asian and West African NS4B orthologues may affect inhibitor binding efficacy, limiting the applicability of drugs developed from Asian dengue strains. This study performs structural and functional characterisation of NS4B from West African dengue strains isolated from Nigerian patients and examines inhibitor sensitivity. Clinical dengue isolates from Ibadan, Lagos, and Benin City will undergo full-genome sequencing, and NS4B coding sequences will be cloned, expressed, and purified. Cryo-electron microscopy and hydrogen-deuterium exchange mass spectrometry will characterise NS4B membrane topology and conformational dynamics. An NS4B-targeted cell-based inhibitor screen using a curated dengue antiviral compound library will identify inhibitors active against West African NS4B. Comparative potency between West African and reference Asian strains will be assessed. Resistance profiling of escape mutants will map inhibitor-binding residues. This doctoral research makes a significant original structural virology contribution by generating the first near-atomic resolution characterisation of dengue NS4B from African strains, providing a molecular foundation for the design of pan-dengue antivirals with efficacy across global dengue diversity. Keywords: dengue virus, NS4B protein, structural virology, antiviral target, West Africa