Sequence Conservation, Radial Distance and Packing Density in Spherical Viral Capsids

Area of Science:

• Structural biology
• Bioinformatics
• Virology

Background:

• Residue conservation indicates protein importance for structure and function.
• Sequence conservation profiles are typically interpreted through evolutionary analysis of homologous sequences.
• Understanding residue importance is key to deciphering protein mechanisms.

Purpose of the Study:

• To investigate the relationship between structural features and sequence conservation in viral icosahedral capsids.
• To determine if structural properties can predict sequence conservation profiles.
• To explore a structural viewpoint for understanding residue conservation.

Main Methods:

• Analysis of sequence conservation profiles in viral icosahedral capsids.
• Calculation of residue distances to the capsid centroid.
• Assessment of local packing density variations within capsid structures.
• Comparison of structural models with sequence conservation data from 51 nonhomologous capsid crystal structures.

Main Results:

• Sequence conservation profiles are inversely proportional to residue-centroid distances.
• Local packing density variations also correlate with sequence conservation.
• Structural patterns observed in viral capsids align with sequence conservation profiles.
• A quantitative link between conservation and structural features (centroid distance, packing density) was established.

Conclusions:

• Residue conservation in viral icosahedral capsids can be determined by structural factors, not solely evolutionary ones.
• Centroid distance and packing density provide a structural basis for understanding residue conservation.
• This study bridges evolutionary and structural perspectives on protein residue conservation.