Self-Assembling Protein Materials with Genetically Programmable Morphology and Size

Materials are challenging to synthetically program down
to the
atom level. Nature, however, excels at creating hierarchical materials
from nanoscale building blocks, a feat that remains a major challenge
in synthetic systems. A deeper understanding of the molecular rules
governing self-assembly would unlock the potential for designing genetically
programmable materials with atomic precision. Hexameric bacterial
microcompartment (BMC-H) proteins offer a powerful model system for
exploring this question. These sequence-defined proteins naturally
assemble into complex architectures and can be expressed biologically,
making them ideal candidates for studying how minor sequence variations
influence supramolecular structure. In this work, we leverage cell-free
protein synthesis (CFPS) alongside immunostaining and super-resolution
microscopy to investigate the self-assembly behavior of two BMC-H
proteins, PduA and PduJ. We find that both proteins form micron- to
millimeter-scale structures when expressed in vitro. Further, we demonstrate how single-point mutation changes lead
PduA and PduJ to form significantly different supramolecular structures
when produced using CFPS. These studies support the future exploration
of self-assembling proteins as programmable scaffolds in broad materials
applications.