Biophysical and biochemical characterization of an HBV cccDNA g-quadruplex targeting therapeutic

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Balderas Figueroa, Gerardo K.
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Biochemistry and Chemistry
Hepatitis B virus (HBV) has chronically infected 296 million people, and it is the leading cause of cirrhosis and hepatocellular carcinoma (HCC). Current treatments target post-transcriptional steps of the viral cycle, which leaves HBV’s covalently closed circular DNA (cccDNA) nuclear reservoirs unaffected. This allows patients to relapse if therapy ceases. We have previously identified a G-quadruplex (G4) forming region in the HBV preCore promoter involved in viral replication. Here, we develop recombinant single-domain antibodies (sdAbs) that can target this G4-forming region. The sdAbs are purified by chromatography, and their interaction with HBV G4 is characterized by biochemical binding assays as well as biophysical techniques. We conclude that sdAbs can be highly structure and sequence specific towards HBV G4. Overall, my work develops a pipeline for G4-targeting that can be used in future HBV cccDNA studies as well as be implemented in the study of other G4s involved in disease.
HBV , Covalently closed circular DNA , cccDNA , G-quadruplex , G4 , Single-domain antibodies , sdABs