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Close, W.

Publications and source records attributed to Close, W..

2 recordsLinked to original sources

Reconfigurable multi-component nanostructures built from DNA origami voxels

In cells, proteins rapidly self-assemble into sophisticated nanomachines. Bio-inspired self-assembly approaches, such as DNA origami, have achieved complex 3D nanostructures and devices. However, current synthetic systems are limited by lack of structural diversity, low yields in hierarchical assembly, and challenges in reconfiguration. Here, we develop a modular system of DNA origami voxels with programmable 3D connections. We demonstrate multifunctional pools of up to 12 unique voxels that can assemble into many shapes, prototyping 50 structures. Multi-step assembly pathways with sequential reduction in conformational freedom were then explored to increase yield. Voxels were first assembled into flexible chains and then folded into rigid structures, increasing yield 100-fold. Furthermore, programmable switching of local connections between flexible and rigid states achieved rapid and reversible reconfiguration of global structures. We envision that foldable chains of DNA origami voxels can be integrated with scalable assembly methods to achieve new levels of complexity in reconfigurable nanomaterials.

synthetic biology↗

Pore structure controls stability and molecular flux in engineered protein cages

Protein cages are a common architectural motif used by living organisms to compartmentalize and control biochemical reactions. While engineered protein cages have recently been featured in the construction of nanoreactors and synthetic organelles, relatively little is known about the underlying molecular parameters that govern cage stability and molecular flux through their pores. In this work, we systematically designed a 24-member library of protein cage variants based on the T. maritima encapsulin, each featuring pores of different size and charge. Twelve encapsulin pore variants were successfully assembled and purified, including eight designs with exceptional and prolonged thermal stability. While pores lined with negatively charged residues resulted in more robust assemblies than their corresponding positively charged variants, we were able to form stable assemblies covering a full range of pore sizes and charges, as observed in seven new cryo-EM structures of pore variants elucidated at resolutions between 2.5-3.6 [A]. Alongside these structures, molecular dynamics simulations and stopped flow kinetics experiments reveal the importance of considering both pore size and surface charge, together with flexibility and rate determining steps, when designing protein cages for controlling molecular flux. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=176 SRC="FIGDIR/small/428512v3_ufig1.gif" ALT="Figure 1"> View larger version (70K): org.highwire.dtl.DTLVardef@725e76org.highwire.dtl.DTLVardef@97a497org.highwire.dtl.DTLVardef@1b6ea1forg.highwire.dtl.DTLVardef@1c4d17f_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗