Dissection of SARS Coronavirus Spike Protein into Discrete Folded Fragments

Area of Science:

• Virology
• Molecular Biology
• Protein Engineering

Background:

• The severe acute respiratory syndrome coronavirus (SARS-CoV) spike protein is crucial for viral entry via cell surface receptor binding and subsequent cell fusion.
• Identifying functional protein fragments is essential for developing targeted antiviral therapies and vaccines.

Purpose of the Study:

• To develop and validate a method for systematically dissecting viral proteins into foldable fragments.
• To identify specific foldable fragments of the SARS-CoV spike protein for potential therapeutic or vaccine development.

Main Methods:

• Utilized DNase I digestion to generate random DNA segments from the SARS-CoV spike protein gene.
• Reassembled DNA segments to create a library of fragments with controlled lengths and random ends.
• Cloned fragments into a vector fused to a green fluorescent protein variant for screening foldable polypeptide fragments.

Main Results:

• Successfully identified two distinct foldable fragments of the SARS-CoV spike protein.
• These fragments correspond to the heptad repeat (HR) region 2, known for anti-SARS peptide activity.
• The method demonstrated efficiency in isolating functional protein domains.

Conclusions:

• The developed method provides a systematic approach to identify foldable protein fragments from viral proteins.
• This technique can be applied to other viral proteins for the discovery of antigen or vaccine candidates.
• Offers an alternative strategy to using full-length proteins or short linear peptides for therapeutic development.