“…Several additional studies with complementary non-neutron-based techniques were carried out in order to characterize the dynamics of proteins in native, molten and denatured states (Buck et al ., 1996; Bai et al ., 2000; Dilg et al ., 2002; Kuzmenkina et al ., 2005; Nienhaus, 2006; Ramboarina and Redfield, 2008; Santos et al ., 2010; Dutta et al ., 2014; Yadav et al ., 2014; Ghosh et al ., 2015; Mondal et al ., 2015; Aznauryan et al ., 2016). In general, FRET (Kuzmenkina et al ., 2005; Nienhaus, 2006; Yadav et al ., 2014; Mondal et al ., 2015) as well as NMR (Buck et al ., 1996; Bai et al ., 2000; Ramboarina and Redfield, 2008; Dutta et al ., 2014) and Mössbauer (Dilg et al ., 2002) as well as NMR (Buck et al ., 1996; Bai et al ., 2000; Ramboarina and Redfield, 2008; Dutta et al ., 2014) and Mössbauer (Dilg et al ., 2002) studies indicate a higher flexibility and dynamic heterogeneity of denatured proteins and molten globules compared with natively folded proteins on timescales ranging from nanoseconds (Buck et al ., 1996; Ramboarina and Redfield, 2008; Dutta et al ., 2014; Yadav et al ., 2014; Mondal et al ., 2015) to micro- to milli-seconds (Buck et al ., 1996; Bai et al ., 2000; Dutta et al ., 2014), and even several seconds, as evidenced by a significant ‘dynamic’ heterogeneity of the structure of the unfolded proteins (Kuzmenkina et al ., 2005; Nienhaus, 2006). By analyzing the average fluorescence lifetime of labeled HSA at different GnHCl concentrations and temperatures, Yadav et al .…”