FIG. 1.

Hydrogen-deuterium exchange recorded in S. acidocaldarius and porcine muscle cytosol adenylate kinases during a temperature gradient experiment. Fractions of unexchanged protons as a function of temperature were calculated from the normalized amide II intensities at 1,546 cm⁻¹ (S. acidocaldarius enzyme) and 1,542 cm⁻¹ (porcine enzyme). The exchange was completed at 56 and 97°C for the porcine and S. acidocaldarius enzymes, respectively. Reprinted from reference 35 with permission of the publisher. (Note that the two enzymes are not directly comparable because the pig enzyme is a monomer whereas the Sulfolobus enzyme is a trimer.)