A Mutation Identified in Neonatal Microcephaly Destabilizes Zika Virus NS1 Assembly in Vitro

Area of Science:

• Virology
• Structural Biology
• Public Health

Background:

• Zika virus (ZIKV) infection caused a major epidemic, linked to neonatal microcephaly, declared a global health emergency.
• No specific vaccines or antiviral drugs are currently available for ZIKV.
• ZIKV nonstructural protein 1 (NS1) is crucial for viral replication and immune evasion.

Purpose of the Study:

• To determine the crystal structure of ZIKV NS1 (172-352) and investigate the impact of a pathogenic mutation.
• To understand the role of Thr233 in NS1 dimer formation and stability.
• To explore potential therapeutic targets for ZIKV infection.

Main Methods:

• Crystal structure determination of ZIKV NS1 (172-352).
• Analysis of the dimeric assembly and the role of the T233A mutation.
• Structural comparison with related flaviviruses and antibody epitopes.

Main Results:

• The crystal structure reveals ZIKV NS1 forms a conserved, head-to-head dimer with a unique β-ladder.
• A pathogenic mutation, T233A, located at the dimer interface, disrupts hydrogen bonding and destabilizes the NS1 dimer.
• Thr233 is a unique residue in ZIKV NS1, critical for dimer stability.

Conclusions:

• The T233A mutation's destabilization of the ZIKV NS1 dimer provides a potential target for antiviral drug development.
• Understanding the structural basis of ZIKV NS1 dimerization is key to designing effective therapies.
• Structural insights into NS1 may aid in developing antibodies against ZIKV and other flaviviruses.