A novel stabilization mechanism accommodating genome length variation in evolutionarily related viral capsids.

How capsids are stabilized and change size is an important part of understanding how to design protein containers and understand viral evolution. We describe a novel capsid stability mechanism that allows the capsid to package a larger genome without changing the capsid architecture and have predicted other capsids using this mechanism. Beyond the evolutionary implications, our findings provide a mechanism to increase the amount of DNA packaged in a capsid, offering a solution to engineer gene delivery systems with larger DNA content, a pressing challenge in gene therapy.