Oligomerization of neutral peptides derived from the JC virus agnoprotein through a cysteine residue

Area of Science:

• Virology
• Structural Biology
• Biochemistry

Background:

• JC virus causes progressive multifocal leukoencephalopathy.
• JC virus agnoprotein is crucial for viral replication and has an oligomerization sequence.
• The structural basis of agnoprotein oligomerization remains unclear.

Purpose of the Study:

• To investigate the structural properties and oligomerization mechanism of JC virus agnoprotein peptides.
• To determine the role of the Agno(22-44) region in viral proliferation and potential transmembrane interactions.

Main Methods:

• Synthesis of 23-amino acid residue peptides (Lys22-Asp44) from JC virus agnoprotein.
• Analysis of peptide secondary structures in aqueous and hydrophobic environments using spectroscopy.
• Investigation of peptide oligomerization under oxidizing conditions, including the use of bismaleimides and thiol-deficient derivatives.

Main Results:

• Peptides adopted a β-sheet structure in aqueous buffer, transitioning to a helical structure in hydrophobic environments.
• Oxidizing conditions induced the formation of peptide dimers and oligomers.
• Oligomerization was enhanced by bismaleimides, and peptides lacking thiol groups did not oligomerize.
• Results suggest the Agno(22-44) peptide may be transmembrane, with a Cys40 disulfide bond initiating oligomerization.

Conclusions:

• The JC virus agnoprotein peptide (Agno(22-44)) exhibits environment-dependent structural changes.
• Oxidation-induced disulfide bond formation, likely involving Cys40, is a key mechanism for agnoprotein oligomerization.
• These findings support a potential transmembrane function for agnoprotein and elucidate its oligomerization pathway.