Folding–unfolding transitions of Rv3221c on the pressure–temperature plane

Abstract

Rv3221c is a biotin-binding protein found in Mycobacterium tuberculosis. It has been reported that an elevated temperature is needed for it to adopt a folded conformation. We determined the complete pressure–temperature phase diagram, and determined the thermodynamical parameters of the denaturation. The phase diagram follows well the Hawley theory. The secondary structure of the protein was found to contain predominantly beta sheet. The pressure unfolding was partially reversible, resulting in pressure-sensitive aggregates, besides the correctly refolded and biotin-bound fraction of proteins.

Keywords:

• pressure
• phase diagram
• Rv3221c
• Mycobacterium tuberculosis
• intrinsically disordered protein

Acknowledgements

This work was supported by grants from the Hungarian Science Foundation (OTKA K77730 and K84133).

Notes

^†This paper was presented at the 7th Conference on High Pressure Bioscience, Biotechnology (HPBB2012) at Otsu, Japan, 29 October–2 November 2012.