The team was led by postdoctoral fellow Gevorg Grigoryan and professor William DeGrado of the Department of Biochemistry and Biophysics in Penn’s Perelman School of Medicine, as well as graduate student Yong Ho Kim of the Department of Chemistry in Penn’s School of Arts and Sciences. Their colleagues included members of the Department of Physics and Astronomy in SAS.
Their research was published in the journal Science.
The team set out to design proteins that could wrap around single-walled carbon nanotubes. Consisting of a cylindrical pattern of carbon atoms tens of thousands of times thinner than a human hair, nanotubes are enticing to nanoengineers as they are extraordinarily strong and could be useful as platform for other nano-structures.
“We wanted to achieve a specific geometric pattern of the atoms that these proteins are composed of on the surface of the nanotube,” Grigoryan said. “If you know the underlying atomic lattice, it means that you know how to further build around it, how to attach things to it. It's like scaffolding for future building.”
The hurdle in making such scaffolds isn’t a lack of information, but a surfeit of it: researchers have compiled databases that list hundreds of thousands of actual and potential protein structures in atomic detail. Picking the building materials for a particular structure from this vast array and assuring that they self-assemble into the desired shape was beyond the abilities of powerful computers, much less humans.
“There's just an enormous space of structural possibilities to weed through trying to figure out which are feasible,” Grigoryan said. “To have a process that can do that quickly, that can look at a structure and say ‘that's not reasonable, that can't be built out of common units,’ would solve that problem.”
The researchers’ algorithm works in three steps, which, given the parameters of the desired scaffolding, successively eliminate proteins that will not produce the right shape. The elimination criteria were based on traits like symmetry, periodicity of binding sites and similarity to protein “motifs” found in nature.
After separating the wheat from the chaff, the result is a list of thousands of candidate proteins. While still a daunting amount, the algorithm makes the protein selection process merely difficult, rather than impossible.
The research team tested their algorithm by designing a protein that would not only stably wrap around a nanotube in a helix but also provide a regular pattern on its exterior to which gold particles could be attached.
“You could use this to build a gold nanowire, for instance, or modulate the optical properties of the underlying tube in desired ways” Grigoryan said.
Next steps will include applying this algorithm for designing proteins that can attach to graphene, which is essentially an unrolled nanotube. Being able to make scaffolds out of customizable array of proteins in a variety of shapes could lead to advances in everything from miniaturization of circuitry to drug delivery.
Engineering these materials in the lab requires a tremendous amount of precision and computational power, but such efforts are essentially mimicking a phenomenon found in even the simplest forms of life.
“The kind of packing that certain viruses have in their viral envelope is similar to what we have here in that they self-assemble. They have protein units that, on their own, form their complicated structures with features that are far beyond the size of any single protein,” Grigoryan said. “Each protein doesn’t know what the final structure is going to be, but it still helps form it. We were inspired by that.”
In addition to Grigoryan, DeGrado and Kim, researchers included Rudresh Acharya of the Department of Biochemistry and Biophysics in the Perelman School of Medicine and Kevin Axelrod, Rishabh M. Jain, Lauren Willis, Marija Drndic and James M. Kikkawa of the Department of Physics and Astronomy in SAS.
Their research was supported by the National Science Foundation and the National Institutes of Health.
Evan Lerner | EurekAlert!
‘Farming’ bacteria to boost growth in the oceans
24.10.2016 | Max-Planck-Institut für marine Mikrobiologie
Calcium Induces Chronic Lung Infections
24.10.2016 | Universität Basel
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
24.10.2016 | Earth Sciences
24.10.2016 | Life Sciences
24.10.2016 | Physics and Astronomy