Nadrian C. Seeman: DNA, not Merely the Secret of Life
Department of Chemistry, New York University, New York, NY 10003, USA.
We build branched DNA species that can be joined using Watson-Crick base pairing to produce N-connected objects and lattices. We have used ligation to construct DNA topological targets, such as knots, polyhedral catenanes, Borromean rings and a Solomon's knot.
Nanorobotics is a key area of application. We have made robust 2-state and 3-state sequence-dependent programmable devices and bipedal walkers. We have constructed 2-dimensional DNA arrays with designed patterns from many different motifs. We have used DNA scaffolding to organize active DNA components. We have used pairs of 2-state devices to capture a variety of different DNA targets. We have constructed a molecular assembly line using a DNA origami layer and three 2- state devices, so that there are eight different states represented by their arrangements. We have demonstrated that all eight products can be built from this system. Recently, we connected the nanoscale with the microscale using DNA origami.
We have self-assembled a 3D crystalline array and reported its crystal structure to 4 Å resolution. We can use crystals with two molecules in the crystallographic repeat to control the color of the crystals. Rational design of intermolecular contacts has enabled us to improve crystal resolution to better than 3 Å. We can now do strand displacement in the crystals to change their color, thereby making a 3D-based molecular machine; we can visualize the presence of the machine by X-ray diffraction.
The use of DNA to organize other molecules is central to its utility. Earlier, we made 2D checkerboard arrays of metallic nanoparticles, and have now organized gold particles in 3D. Most recently, we have ordered triplex components and a semiconductor within the same lattice. Thus, structural DNA nanotechnology has fulfilled its initial goal of controlling the internal structure of macroscopic constructs in three dimensions. A new era in nanoscale control awaits us.
This research has been supported by the following grants to NCS: CHE-1708776, NSF EFRI-1332411 and CCF-1526650 from the NSF, RGP0010/2017 from Human Frontiers Science Program, DE-SC0007991 from the US Department of Energy (DOE) for DNA synthesis and partial salary support, and Grant GBMF3849 from the Gordon and Betty Moore Foundation.
Upgrade of the workflow for cryo-electron tomography and microscopy
The CIISB Cryo-electron microscopy core facility at CEITEC Masaryk University is expanding its services in the sample preparation for electron microscopy. The facility has recently acquired high-pressure freezer Leica EM ICE for vitrification of bulky biological specimen (up to 200 mm thickness). In addition, the freeze-substitution unit Leica EM AFS2 for resin embedding of the high-pressure frozen samples and the ultramicrotom Leica EM UC7 with the adapter for cryo-ultramicrotomy were purchased in order to provide the facility users with the complete workflow for preparation of thin section samples for both room-temperature electron microscopy and cryo-electron microscopy.
Emerging Topics in Biomolecular Magnetic Resonance – Nick Cox & Kendra Frederick
The series Emerging topics in Biomolecular Magnetic Resonance will continue on July 9th at 16:00 CEST with the following lecturers and topics:
Nick Cox (Australian National University): Spin state evolution during the biological water splitting reaction
Kendra Frederick (UT Southwestern): In cell structural biology enabled by DNP MAS NMR
Emerging Topics in Biomolecular Magnetic Resonance – 4th edition
The series Emerging topics in Biomolecular Magnetic Resonance will continue on June 25th at 16:00 CEST with the following lecturers and topics:
Melinda J. Duer (University of Cambridge): Understanding extracellular matrix disease states with solid-state NMR?
Claudio Luchinat (University of Florence): NMR for metabolomics: again the ‘second best’ technique?
Emerging Topics in Biomolecular Magnetic Resonance – 3rd edition
The series Emerging topics in Biomolecular Magnetic Resonance will continue on June 18th at 16:00 CEST with the following lecturers and topics:
Tuo Wang (Louisiana State University): Elucidation of carbohydrate structure in plant biomass and fungal pathogens using solid-state NMR and DNP methods
Rina Rosenzweig (Weizmann Institute of Science): Molecular Chaperones in Protein Disaggregation - What we can learn from NMR