Proteins: New class of materials discovered

Arrangement of protein concanavalin A molecules in two different protein crystalline frameworks.

Arrangement of protein concanavalin A molecules in two different protein crystalline frameworks. © Fudan Universität/HZB

German-Chinese research team gleans seminal insights into protein crystalline frameworks at HZB's BESSY II

Scientists at the Helmholtz Center Berlin (HZB) along with researchers at China’s Fudan University have characterized a new class of materials called protein crystalline frameworks (PCFs).

Thanks to certain helper substances, in PCFs proteins are fixated in a way so as to align themselves symmetrically, forming highly stable crystals. Next, the HZB and Fudan University researchers are planning on looking into how PCFs may be used as functional materials. Their findings are being published today in the scientific journal Nature Communications (DOI: 10.1038/ncomms5634).

Proteins are sensitive molecules. Everyone knows that – at least from having boiled eggs. Under certain circumstances – like immersion in boiling water – they denature, losing their natural shape, and becoming hard. True, researchers have been able to handle these substances for some time now, even to the point of crystallizing them in their native state. Admittedly, though, this does require considerable effort, but it is the only way how researchers can find out the structure of these substances at high resolution. Moreover, protein crystals are extremely fragile, highly sensitive and hard to handle.

Now, for the first time ever, scientists at China's Fudan University have managed to work around these downsides by linking the protein concanavalin A to helper molecules belonging to the sugar family, and to the dye rhodamin. The concanavalin molecules that have been thus fixated tended to arrange themselves symmetrically within the helper molecule framework, forming crystals, in which the proteins achieve high stability and are intricately interconnected – into a protein crystalline framework.

Developing molecular structures like these is pointless unless you know exactly how they form and what their structure looks like at the level of the atoms. During the quest for suitable experimental methods, the Shanghai researchers turned to a Chinese scientist working at the HZB for help. She called her colleagues' attention to the MX beamlines at the HZB's electron storage ring BESSY II.

"Here at the HZB, we were able to offer them our highly specialized crystallography stations – the perfect venue for characterizing PCFs at high resolutions," says Dr. Manfred Weiss, one of the leading scientists working at the HZB-MX laboratory. It quickly became clear that the helper molecules even allowed the researchers to decide how powerfully they wanted them to penetrate the protein frameworks. "This gives the PCFs a great deal of flexibility and variability, which we’ll always keep in mind when doing research on potential applications," says Manfred Weiss.

Original publication: Sakai, F. et al. Protein crystalline frameworks with controllable interpenetration directed by dual supramolecular interactions. Nat. Commun. 5:4634 doi: 10.1038/ncomms5634 (2014).


You might also be interested in

  • Spintronics at BESSY II: Domain walls in magnetic nanowires
    Science Highlight
    Spintronics at BESSY II: Domain walls in magnetic nanowires
    Magnetic domains walls are known to be a source of electrical resistance due to the difficulty for transport electron spins to follow their magnetic texture. This phenomenon holds potential for utilization in spintronic devices, where the electrical resistance can vary based on the presence or absence of a domain wall. A particularly intriguing class of materials are half metals such as La2/3Sr1/3MnO3 (LSMO) which present full spin polarization, allowing their exploitation in spintronic devices. Still the resistance of a single domain wall in half metals remained unknown. Now a team from Spain, France and Germany has generated a single domain wall on a LSMO nanowire and measured resistance changes 20 times larger than for a normal ferromagnet such as Cobalt.
  • Graphene on titanium carbide triggers a novel phase transition
    Science Highlight
    Graphene on titanium carbide triggers a novel phase transition
    Researchers have discovered a Lifshitz-transition in TiC, driven by a graphene overlayer, at the photon source BESSY II. Their study sheds light on the exciting potential of 2D materials such as graphene and the effects they can have on neighboring materials through proximity interactions.
  • Alexander von Humboldt Foundation Grant for Dr. Jie Wei
    Alexander von Humboldt Foundation Grant for Dr. Jie Wei
    In April, Dr. Jie Wei started his research work in the Helmholtz Young Investigator Group Nanoscale Operando CO2 Photo-Electrocatalysis at Helmholtz-Zentrum Berlin (HZB) and Fritz Haber Institute (FHI) of the Max Planck Society. Wei received one of the highly competitive Humboldt postdoctoral research fellowships and will pursue his two-year project under the guidance of the academic hosts Dr. Christopher Kley and Prof. Dr. Beatriz Roldan Cuenya.