Title: Self-assembly of Model Microtubules
Presenter: Mark Stevens
Affiliation: Sandia National Laboratories
Abstract: Self-assembly plays a central role in producing ordered superstructures. The crucial question is to identify the necessary features that a macromolecular monomer must have in order to drive self-assembly into a desired complex structure. In this talk I will present our recent work on the self-assembly of model microtubules. The model monomer has a wedge-shape with lateral and vertical binding sites. Using MD simulations with LAMMPS, we show that such building blocks indeed self-assemble into tubular structures when the interaction strength is in an appropriate range. In addition, helical tubes are frequently formed even though the monomer is nonchiral. The occurrence of the helical tubes is related to the large overlap of energy distributions for nonhelical and helical tubes. To enhance structural control of the self-assembly, we added chirality and a lock-and-key mechanism to the model. We could control both the pitch of the helicity and the twist deformation of the tube by modifying the locations of the binding sites and their interaction strengths. Our results shed new light on the structure of in vitro microtubules formed with various numbers of protofilaments of tubulins, which also exhibit similar twisted structures and various pitches, and have determined the fundamental features of macromolecular monomers for self-assembly into a tubular structure.