DNA Origami as Seeds for Promoting Protein Crystallization.

This study reports the first experimental evidence of DNA origami as a seed resulting in the increase in probability of protein crystallization. Using the DNA origami constructed from long single-stranded M13 DNA scaffolds folded with short single-stranded DNA staples, it was found that the addition of the DNA origami in concentrations of 2-6 nM to mixtures of a well-characterized protein (catalase) solution (1.0-7.0 mg/mL) resulted in a higher proportion of mixtures with successful crystallization, up to 11× greater. The improvement in crystallization is evident particularly for mixtures with low concentrations of catalase (<5 mg/mL). DNA origami in different conformations of a flat rectangular sheet and a tubular hollow cylinder were examined. Both conformations improved the crystallization as compared to control experiments without M13 DNA or nonfolded M13 DNA but exhibited little difference in the extent of protein crystallization improvement. This work confirms the predictions of the potential use of DNA origami to promote protein crystallization, with potential application to systems with limited protein availability or difficulty in crystallization.

An Addressable 2D Heterogeneous Nanoreactor to Study the Enzyme-Catalyzed Reaction at the Interface.

Membrane plays significant role in cellular enzymatic reactions. To better understand its function on membrane integral or bound enzymes, DNA origami and frame-guided assembly strategy are combined to construct a given-size, addressable enzyme-containing nanomembrane as a heterogeneous reactor to explore the enzymatic catalyst reaction on the membrane. The enzymes in the membrane are located precisely. This new kind of membrane can enrich hydrophobic substrate molecules in aqueous solution to the embedded enzymes. Otherwise, this nanomembrane shows the capability of substrate selectivity, which plays important role in the highly efficient and specific properties of enzymes in vivo.

DNA nanochannels.

Transmembrane proteins are mostly nanochannels playing a highly important role in metabolism. Understanding their structures and functions is vital for revealing life processes. It is of fundamental interest to develop chemical devices to mimic biological channels. Structural DNA nanotechnology has been proven to be a promising method for the preparation of fine DNA nanochannels as a result of the excellent properties of DNA molecules. This review presents the development history and current situation of three different types of DNA nanochannel: tile-based nanotube, DNA origami nanochannel, and DNA bundle nanochannel.

Cuboid Vesicles Formed by Frame-Guided Assembly on DNA Origami Scaffolds.

We describe the use of a frame-guided assembly (FGA) strategy to construct cuboid and dumbbell-shaped hetero-vesicles on DNA origami nanostructure scaffolds. These are achieved by varying the design of the DNA origami scaffolds that direct the distribution of the leading hydrophobic groups (LHG). By careful selection of LHGs, different types of amphiphiles (both polymer and small-molecule surfactants) were guided to form hetero-vesicles, demonstrating the versatility of the FGA strategy and its potential to construct asymmetric and dynamic hetero-vesicle assemblies with complex DNA nano-scaffolds.

Precisely Controlled 2D Free-Floating Nanosheets of Amphiphilic Molecules through Frame-Guided Assembly.

2D assembly of amphiphilic molecules in aqueous solution is a challenging and intriguing topic as it is normally thermodynamically unfavorable. However, through frame-guided assembly strategy and using DNA origami as the frame, monodispersed and shape-defined nanosheets are prepared. As leading hydrophobic groups (LHGs) are anchored on the frames, amphiphilic molecules in aqueous solution are guided to assemble in the hydrophobic region. By adjusting the distribution of the LHGs, the size and shape of the assemblies can be controlled precisely.

A switchable DNA origami nanochannel for regulating molecular transport at the nanometer scale.

A nanochannel with a shutter at one end was built by DNA nanotechnology. Using DNA hybridization the shutter could be opened or closed, influencing the transport of materials through the channel. This process was visualized by an enzyme cascade reaction occurring in the structure.

Preparation and self-folding of amphiphilic DNA origami.

Amphiphilic DNA origami is prepared by dressing multiple hydrophobic molecules on a rectangular single layer DNA origami, which is then folded or coupled in sandwich-like structures with two outer DNA origami layer and one inner hydrophobic molecules layer. The preference to form different kinds of structures could be tailored by rational design of DNA origami.

Frame-guided assembly of vesicles with programmed geometry and dimensions.

In molecular self-assembly molecules form organized structures or patterns. The control of the self-assembly process is an important and challenging topic. Inspired by the cytoskeletal-membrane protein lipid bilayer system that determines the shape of eukaryotic cells, we developed a frame-guided assembly process as a general strategy to prepare heterovesicles with programmed geometry and dimensions. This method offers greater control over self-assembly which may benefit the understanding of the formation mechanism as well as the functions of the cell membrane.