Figure 5.

K₂ interaction with LDH. (A) ¹⁵N-HSQC of 0.1 mM of K₂ collected in the absence (black contours) or the presence (gray contours) of 0.3 mM LDH. The peak labels show the residue number and single letter amino acid code of K₂. B: Cryoprotection of LDH by K₂ is mediated by weak electrostatic interactions. The bar graph shows the percent LDH activity of samples assayed in the presence and the absence of salt with and without 1 μg/mL K₂. The data represent n = 6 measurements with the error bar corresponding to the standard deviation. Unfrozen samples with no NaCl, black bars; frozen samples with no NaCl, light gray; unfrozen samples with 1M NaCl, dark gray; frozen samples with 1M NaCl, white.