PiP2 favors an α-helical structure of non-recombinant Hsp12 of Saccharomyces cerevisiae.

Hsp12 is a small heat shock protein of Saccharomyces cerevisiae upregulated in response to various stresses. Non recombinant Hsp12 has been purified and characterized. Using circular dichroism (CD), Isothermal Titration Calorimetry (ITC) and Differential Scanning Calorimetry (DSC), it has been demonstrated that the native Hsp12 is monomeric and intrinsically disordered (IDP). Hsp12 gains in structure in the presence of specific lipids (PiP2). The helical form binds to liposomes models membrane with high affinity, leading to their rigidification. These results suggest that hydrophobic and ionic interactions are involved. Hsp12 is most likely a membrane chaperone expressed during stresses in Saccharomyces cerevisiae.