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Topological Entanglement of Linear Catenanes: Knots and Threadings

2023; American Chemical Society; Volume: 12; Issue: 9 Linguagem: Inglês

10.1021/acsmacrolett.3c00315

2161-1653

Zahra Ahmadian Dehaghani, Pietro Chiarantoni, Cristian Micheletti,

Protein Structure and Dynamics

We used molecular dynamics simulations to investigate the self-entanglements of the collapsed linear catenanes. We found two different types of topologically complex states. First, we observed numerous long-lived knotting events of the catenane backbone. However, comparison with conventional polymers reveals that knots are suppressed in catenanes. Next, we observed topologically complex states with no analogue in polymers, where a concatenated ring was threaded by other near or distal rings sliding through it. Differently from knots, these threaded states can disentangle by becoming fully tightened. A detailed thermodynamic and microscopic analysis is employed to rationalize the persistence of threaded states, which can survive significant internal reorganizations of the entire catenane. We finally discuss the broader implications of these previously unreported types of entanglements for other systems, such as noncollapsed and interacting catenanes.