HCV NS3 protein fragments having helicase activity and improved
申请人:Chiron Corporation
公开号:US05989905A1
公开(公告)日:1999-11-23
The Hepatitis C Virus (HCV) NS3 protein contains amino acid motifs of a serine proteinase, a nucleotide triphosphatase (NTPase), and an RNA helicase. A carboxy fragment of the HCV NS3 protein was purified and possessed RNA helicase activity. Detections from the amino terminus resulted in the protein becoming soluble. Deletions from the carboxy terminus do not result in a loss of helicase activity until at least 50 amino acids are deleted. The helicase activity requires ATP and divalent cations such as Mg.sup.2+ and Mn.sup.2+. The helicase activity was blocked by monoclonal antibody specific to the HCV NS3 protein.
Synthesis of peptides related to hydra head activator (HA; pGlu-Pro-Pro-Gly-Gly-Ser-Lys-Val-Ile-Leu-Phe-OH) was performed by the solution method. The analogs synthesized were Tyr11-HA, des-Phe11-HA, Arg1-HA and Phe5-HA. Antisera were prepared by immunizing three rabbits with the synthetic HA. Two anti-HA-antisera with sufficient titer were obtained. An HA-radioimmunoassay system, developed by using an antiserum (ASH-04) and 125I-Tyr11-HA as a tracer, was found to be sensitive and specific to HA.