Decoding Structural Properties of a Partially Unfolded Protein Substrate: En Route to Chaperone Binding
A) Emission spectra of free 1–8 ANS (final 10 μM) in buffer solution and bound to DapA incubated at 308 K and 333 K are plotted. The spectra was recorded after incubation with DapA (final 2 μM) subjected to thermal denaturation by gradual increase in temperature. B) “Exposed Hydrophobic Surface Contribution” (EHSC) as a function of major conformational transition events in I1 and I2 are plotted. Four primary events contribute to conformational transitions in DapA, namely, i) α-helix to random coil ii) β-sheet to random coil iii) random coil to β-sheet, and iv) α-helix to β-sheet. The contribution of each event is attributed to the surface exposed hydrophobic patches i.e., how much percentage of α-helix to random coil event is giving rise to the total hydrophobicity in intermediate structures. C-E) Representative snapshots of N, I1 and I2 showing a clear increase in exposed hydrophobic patches in intermediates with respect to native, where exposed non-polar atoms of the contributing residues are highlighted in red color.