Refined Capsid Structure of Human Adenovirus D26 at 3.4 Å Resolution

Area of Science:

• Structural Biology
• Virology
• Biochemistry

Background:

• Adenoviruses are critical viral vectors for vaccine development against emerging and chronic diseases.
• Human adenovirus D26 (HAdV-D26) is a key vector, necessitating detailed structural understanding.

Purpose of the Study:

• To improve the resolution and refine the structural model of the HAdV-D26 capsid.
• To gain deeper insights into protein-protein interactions within HAdV capsids.
• To inform the design of modified adenoviral vectors with enhanced properties.

Main Methods:

• Reprocessing of a previous cryo-electron microscopy dataset for HAdV-D26.
• Generation of a refined 3.4 Å resolution structural model of the HAdV-D26 capsid.

Main Results:

• A refined HAdV-D26 capsid model revealing previously unobserved structural details.
• Identification of a processed peptide of protein VIII within mature virions.
• Observed reorientation of the IIIa protein's appendage domain (APD) and its altered interactions with hexon bases.
• Characterization of the conserved conformation and stacking interactions of cleaved N-terminal segments of pre-protein VI (pVIn) within hexon cavities.
• Insights into the binding of clotting factors like FX and PF4 to adenoviral vectors.

Conclusions:

• The improved HAdV-D26 structure enhances understanding of adenoviral capsid protein interactions.
• This structural refinement facilitates the engineering of more effective adenoviral vectors for vaccine applications.
• The study provides crucial data for optimizing adenoviral vector design and function.