Hepatitis C Virus (HCV) is a significant global health concern, affecting nearly 3% of the world’s population. It is a major cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. The virus was first identified in 1989 and belongs to the Flaviviridae family. HCV is an enveloped single-stranded RNA virus with a genome of approximately 9.6 kb, flanked by untranslated regions (UTRs) at its 5’ and 3’ ends .
The HCV core protein is the first protein translated from the HCV genome and plays a crucial role in forming the viral nucleocapsid. The mature core protein is a 21-kDa protein that binds to the host-derived lipid membrane and HCV RNA . The core protein consists of the first 191 amino acids of the HCV polyprotein and can be divided into three domains based on hydrophobicity . Domain 1 (amino acids 1-117) contains mainly basic residues with two short hydrophobic regions .
Recombinant HCV core proteins, particularly the N-terminal 120 amino acids, have been extensively studied for their ability to self-assemble into nucleocapsid-like particles. These particles exhibit a regular, spherical morphology with a diameter of approximately 60 nm . The self-assembly process requires structured RNA molecules, and the inclusion of the carboxy-terminal domain of the core protein can modify the assembly pathway .
The study of recombinant HCV core proteins provides valuable insights into the protein-protein and protein-RNA interactions critical for HCV assembly. These insights are essential for understanding the molecular details of HCV assembly and for developing high-throughput screening methods for assembly inhibitors . Additionally, the recombinant core protein’s ability to self-assemble into nucleocapsid-like particles offers novel opportunities for vaccine development and therapeutic interventions.