Formation of critical oligomers is a key event during conformational transition of recombinant syrian hamster prion protein.

We have investigated the conformational transition and aggregation process of recombinant Syrian hamster prion protein (SHaPrP90-232) by Fourier transform infrared spectroscopy, circular dichroism spectroscopy, light scattering, and electron microscopy under equilibrium and kinetic conditions. SHaPrP90-232 showed an infrared absorbance spectrum typical of proteins with a predominant alpha-helical structure both at pH 7.0 and at pH 4.

Are there temperature-dependent structural transitions in the "intrinsically unstructured" protein prothymosin alpha?

Prothymosin alpha, a typical member of the class of the so-called "intrinsically unstructured" proteins, adopts a random-chain conformation under physiological environmental conditions. An apparent formation of ordered secondary structure and a moderate compaction are observed upon the change from neutral to acid pH at room temperature. We have addressed the question of whether there are temperature-dependent changes of the conformational state of prothymosin alpha at low pH using circular dichroism spectroscopy and static and dynamic light scattering.