Capturing chemical reactions inside biomolecular condensates with reactive Martini simulations

Abstract

Biomolecular condensates are phase separated systems that play an important role in the spatio-temporal organisation of cells. Their distinct physico-chemical nature offers a unique environment for chemical reactions to occur. The compartmentalisation of chemical reactions is also believed to be central to the development of early life. To demonstrate how molecular dynamics may be used to capture chemical reactions in condensates, here we perform reactive molecular dynamics simulations using the coarse-grained Martini forcefield. We focus on the formation of rings of benzene-1,3-dithiol inside a synthetic peptide-based condensate, and find that the ring size distribution shifts to larger macrocycles compared to when the reaction takes place in an aqueous environment. Moreover, reaction rates are noticeably increased when the peptides simultaneously undergo phase separation, hinting that condensates may act as chaperones in recruiting molecules to reaction hubs. Biomolecular condensates show distinct physicochemical properties that may affect the rate of enzymatic activity and control cellular redox reactions, however, their influence on the other types of chemical reaction remains underexplored. Here, the authors use reactive Martini simulations to probe the non-enzymatic macrocyclization reaction of benzene-1,3-dithiol in the presence of peptide condensates.