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Biomolecular condensates are increasingly recognized as key regulators of chromatin organization, yet how their formation and properties arise from protein sequences remains incompletely understood. Cross-species comparisons can reveal both conserved functions and significant evolutionary differences. Here, we integrate in vitro reconstitution, molecular dynamics simulations, and cell-based assays to examine how Drosophila and human variants of Polyhomeotic (Ph)—a subunit of the PRC1 chromatin regulatory complex— drive condensate formation through their sterile alpha motif (SAM) oligomerization domains. We identify divergent interactions between SAM and the disordered linker connecting it to the rest of Ph. These interactions enhance oligomerization and modulate both the formation and properties of reconstituted condensates. Oligomerization influences condensate dynamics but minimally impacts condensate formation. Linker-SAM interactions also affect condensate formation in Drosophila and human cells and growth in Drosophila imaginal discs. Our findings show how evolutionary changes in disordered linkers can finetune condensate properties, providing insights into sequence-function relationships. 

Among the many natural biomaterials for which information on atomic-level structure and reorientational motion can offer essential clues to function, insoluble multi-component composites with limited degrees of order are among the most challenging to study. Despite its limited sensitivity, solid-state NMR (ssNMR) is often the technique of choice to ferret out these details in carbon- and nitrogen-rich materials: this spectroscopic approach can probe many biomaterials in their native or near-native states, either with or without the introduction of stable NMR-active isotopes, or with the assistance of dynamic nuclear polarization technology. During a span of close to four decades, such research targets and ssNMR approaches have been exemplified by insects, a diverse and evolutionarily agile group of organisms with global impacts that include ecology, agriculture, and human disease. In this short review, we present case studies on insect cuticles that range from protective exoskeletons and egg capsules to the wing structures that enable flight and showcase nature’s awe-inspiring beauty, highlighting the use of ssNMR spectroscopy to profile chemical composition, elucidate macromolecular architecture, and monitor metabolic development in these fascinating biological assemblies.