Secondary structure content of PsbP.

The amide I band was analyzed from Raman spectra acquired on protein samples in solution, glassy state (DCDR), and crystals. Spectra were deconvoluted using the pattern recognition least-squares method (LSA) [38] and two reference intensity profile methods (3-RIP and 4-RIP) [39]. Secondary structure content is given as % of residues ± standard deviation calculated from the standard deviations for each respective reference set. All % values are based on the full sequence of 190 residues; the number of residues in each secondary structure type is given in parentheses. The 4-RIP method does not normalize to 100%. The categories α-ordered and α-disordered structures reflect helix mobility. In the model, the 15 native and 4 remaining His-tag residues were assigned as unordered, and added to the 48 residues observed in that conformation.