Formation of supramolecular protein structures on gold surfaces

Abstract

Recent research has highlighted the exciting possibilities enabled by the use of protein structures as nanocomponents to form functional nanodevices. To this end, control over protein-protein and protein-surface interactions is essential. In this study, the authors probe the interaction of human peroxiredoxin 3 with gold surfaces, a protein that has been previously identified as having potential use in nanotechnology. Analytical ultracentrifugation and transmission electron microscopy revealed the pH mediated assembly of protein toroids into tubular structures across a small pH range. Quartz crystal microbalance with dissipation measurements showed differences in absorbed protein mass when pH is switched from pH 8.0 to 7.2, in line with the formation of supramolecular structures observed in solution studies. Scanning tunneling microscopy under ambient conditions showed that these protein tubes form on surfaces in a concentration dependent manner, with a tendency for protein adsorption and supramolecular assembly at the edges of Au(111) terraces. Finally, self-assembled monolayer modification of Au surfaces was explored as a means to control the adsorption and orientation of pH triggered protein structures.

Self-assembly of toroidal proteins explored using native mass spectrometry

“… 23 , 24 Histidine tags located at the protein N-terminus (His 6 -tag) both stabilise peroxiredoxin rings, 25 as well as alter the transition pH at which self-assembly into HMW protein tubes occurs. 26 The peroxiredoxin N-termini project into the inner cavity of the ring, and His 6 -tags have been used for binding useful moieties, 18 and for binding to surfaces. 26 The presence or absence of the histidine tag thus facilitates a tuneable system by which protein supramolecular self-assembly complexes can be designed, which could be applied to other self-assembling protein systems.…”

“… 26 The peroxiredoxin N-termini project into the inner cavity of the ring, and His 6 -tags have been used for binding useful moieties, 18 and for binding to surfaces. 26 The presence or absence of the histidine tag thus facilitates a tuneable system by which protein supramolecular self-assembly complexes can be designed, which could be applied to other self-assembling protein systems. § §Cleaved refers to protein with the N-terminal His 6 -tag removed using TEV protease cleavage.…”

Taking Advantage of the Morpheein Behavior of Peroxiredoxin in Bionanotechnology

“…For instance, hPrxIII engineered with a N-terminal polyHis tag forms rings resembling the untagged protein at pH 8.0, 29 as confirmed by analytical ultracentrifugation (AUC). 75 Alike hPrxIII, rings can be obtained using the N-terminal polyHis-tagged Sm PrxI at pH 7.6 ( Figure 4 b) 38 , 46 characterized by the pentagonal decameric assembly (pentamer of homodimers; PDB: 3ZTL). 37 The rings appear as spherical globules with height profile of ∼12 or ∼4 nm when imaged by atomic force microscopy (AFM) and, notably, are stable after heating to 75 °C, therefore demonstrating remarkable thermostability.…”

“…Scanning tunneling microscopy (STM) show that that the rings preferentially bind face-on to the gold appearing as discrete globules with 15 nm diameter and 0.5 nm thickness, thus creating a flat protein coating ( Figure 10 a). 75 To note, the stability of the interaction is increased by treating the gold surface with a self-assembling monolayer (SAM) of SH-nitrilotriacetic acid (NTA-thiol). 75 …”

Highly ordered protein cage assemblies: A toolkit for new materials

“…Prxs belong to an abundant family of peroxide-dependent antioxidant enzymes within cells (Perkins, Nelson, Parsonage, Poole, & Karplus, 2015;Rhee, Chae, & Kim, 2005). Although Prxs can be found as CP dimers in solution, decameric toroidal capsids with an approximate outer diameter of 13 nm, an inner pore of 6 nm, and a height of 4 nm are more commonly found (Ardini et al, 2014;Domigan et al, 2017;Jang et al, 2004) (Figure 1g). Furthermore, larger aggregates and higherorder complexes such as toroid stacks or spherical cages are naturally found under reducing conditions (Lowther & Haynes, 2011;Phillips et al, 2014).…”