Biochemistry 2017 02 07() doi 10.1021/acs.biochem.6b01141
The HIV-1-protease is a complex protein which in its active form adopts a homodimer dominated by -sheet structures. We have discovered a cold-denatured state of the monomeric subunit of HIV-1-protease which is populated above 0ºC and therefore directly accessible to various spectroscopic approaches. From NMR secondary chemical shifts, temperature coefficients and protein dynamics we suggest that the cold denatured state populates a compact wet globule containing transient non-native-like -helical elements. From the linearity of the temperature coefficients and the hydrodynamic radii, we propose that the overall architecture of the cold-denatured state is maintained over the temperature range studied.