Compaction and clustering of a heterogeneous polymer by biomolecular crowding

What is it about?

Inspired by the organization of bacterial chromosomes, we use computer simulations to examine how a ring-shaped chain, made of different-sized segments, collapses and clusters in crowded spaces. The chain is heterogeneous in structure, with large and small segments arranged so that the larger ones are evenly spaced along the chain. In a medium crowded by free particles, chain molecules, similar to chromosomes, collapse due to the “push” of surrounding particles. Our findings show that the collapse of a heterogeneous chain by crowding particles happens together with the clustering of its large segments: when large segments are big enough, chain collapse and clustering of large segments happen at the same time at a biologically meaningful level of crowding. We also found that placing the chain in a confined space, like a cylinder, made these crowding effects even stronger. Our study suggests that phase separation and clustering are important features in how bacterial chromosomes are organized.

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Photo by digitale.de on Unsplash

Photo by digitale.de on Unsplash