Zika virus nonstructural protein 5 RNA-dependent RNA polymerase (ZIKV NS5 RdRp)

Zika virus nonstructural protein 5 (NS5) RNA-dependent RNA polymerase is the main enzyme responsible for replication of the Zika virus RNA genome. NS5 is the largest and most conserved ZIKV protein, comprising two functional domains: a C-terminal RNA-dependent RNA polymerase (RdRp) for viral RNA synthesis, and an N-terminal methyltransferase for RNA capping. The RdRp domain mediates de novo synthesis of RNA, a process essential for the production of new viral genomes. The methyltransferase domain is responsible for RNA cap formation, enhancing genome stability and translation. NS5 critically suppresses host immune responses by antagonizing interferon signaling, and may modulate host transcription, contributing to disease pathogenesis, including abnormal neurodevelopment. The unique structure and essential role of NS5 RdRp make it a prime therapeutic target for antiviral drug development against Zika virus infection. Inhibitors designed for similar flavivirus polymerases (e.g., dengue, hepatitis C) are being explored for anti-Zika activity, utilizing both nucleoside analogues and structure-guided non-nucleoside inhibitors. NS5 is specific to flaviviruses and lacks direct human analogs, enhancing its suitability as an antiviral drug target.

Other names

ZIKV NS5 polymeraseZika virus NS5NS5 RNA-dependent RNA polymeraseNS5 RdRp

Inhibition of RNA polymerase activity via chain termination (nucleoside/nucleotide analogues) Occupation of active site or priming loop pocket to prevent RNA elongation (non-nucleoside inhibitors) Competitive inhibition of the substrate binding site, including SAM or RNA cap analogue sites (for methyltransferase inhibitors) Blockade of RNA synthesis and viral replication