We fit the spectra of seven other water subsets reported in Konstantinovsky et al. (Figures ). These subsets include (1) water associated with the backbone of LK7b, (2) water associated with sidechains, (3) water molecules in the backbone subset but not forming hydrogen bonds with the protein, (4) water hydrogen-bonded to carbonyl groups on the backbone, (5) water forming very short hydrogen bonds with the carbonyl groups on the backbone (a distance of <1.6 Å between hydrogen and acceptor), (6) water molecules in the sidechain subset but not making hydrogen bonds to the protein, and ( ) water molecules hydrogen-bonded to lysine sidechains. We have obtained very similar results. Altogether, these analyses validate our model (Figure ) and illustrate the advantage of the new fitting approach. Based on these analyses, we can now infer frequency distributions from chiral SFG spectra and interpret the physical meaning of peak locations.