PLEASE NOTE: the paper by Anthony et al. in Structure was subsequently retracted due to the discovery of research misconduct by its first author, see http://www.cell.com/structure/abstract/S0969-2126(14)00016-1.
In economically turbulent times gold is acquired and held onto as a stable, secure commodity – it’s the “gold standard”. Gold of course has been a source of wealth as a precious metal and source of beauty. Importantly, gold is an incredibly dense and malleable transition metal that maintains its beauty and strength over long time periods, existing as a stable pure solid. Gold has also been an important subject of study and use in life science applications as well as in the physical sciences and in the clinical realm – not only as a source for fillings or a bridge after the dentist deals with your teeth issues!
Kelsey Anthony, a doctoral student in the Brandeis Biochemistry program as well at the Quantitative Biology program, has been working with gold in the Pomeranz Krummel lab to study biopolymer structure. The properties of gold most important in these applications are that it is a pure and stable solid, forms monodisperse spheroidal aggregates, is electron dense, and has the property of anomalously scattering x-rays at specific wavelengths. All these properties combined make gold an optimal metal to be “visualized”. In her most recent application of gold, in press in the journal Structure, Kelsey collaborated with a group at the University of Osnabruek in Germany in the synthesis of a reagent conjugated with monodisperse gold clusters or nanoparticles (called AuNPtris-NTA, see figure) and employed this reagent to localize protein(s) of interest in large multi-protein assemblies.
The experiment most visually striking to demonstrate the utility of this new “gold reagent” involved attaching it to a protein that interacts with itself to form a ring shaped structure. When visualized using the electron microscope, the gold clusters or nanoparticles site-specifically attached to the protein appear as extremely dense black spots due to their significant scattering of electrons as a consequence of the gold’s electron dense structure.
In essence, Kelsey has created a stunning golden microscopic studded ring. Next up, employing this gold conjugated reagent in other new ways.
See: Anthony et al., High-Affinity Gold Nanoparticle Pin to Label and Localize Histidine-Tagged Protein in Macromolecular Assemblies, Structure (2014)
