RNA-dependent RNA polymerase

RNA-dependent RNA polymerase (RdRp) is an essential protein found in all RNA viruses. This enzyme is responsible for the replication of RNA from an RNA template, a process known as RNA replication. RdRp is the key component of the viral replication complex in RNA viruses.

Function[edit]

RdRp catalyzes the synthesis of a complementary RNA strand using a template RNA strand. The process of RNA replication by RdRp begins with the binding of the RdRp to the 3' end of the virus RNA, followed by the synthesis of a complementary RNA strand. The newly synthesized RNA strand then serves as a template for the synthesis of additional RNA strands.

Structure[edit]

The structure of RdRp is highly conserved among RNA viruses, indicating a common evolutionary origin. The core structure of RdRp is a right-handed domain structure, which resembles a cupped hand. This structure is composed of three subdomains: the fingers, palm, and thumb subdomains. The active site of the enzyme, where RNA synthesis occurs, is located in the palm subdomain.

Role in Viral Replication[edit]

In RNA viruses, RdRp is essential for the replication of the viral genome. The enzyme synthesizes a negative-sense RNA strand using the positive-sense RNA genome of the virus as a template. This negative-sense RNA strand then serves as a template for the synthesis of additional positive-sense RNA genomes.

Inhibitors[edit]

Given the essential role of RdRp in the life cycle of RNA viruses, this enzyme is a major target for antiviral drugs. Several RdRp inhibitors have been developed for the treatment of infections caused by RNA viruses, such as Hepatitis C and COVID-19.