Conformational free energy of armadillo metmyoglobin

• Published in: International Journal of Peptide and Protein Research
• Main Authors: KELLY, LENORE, HOLLADAY, LESLIE A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1990
• Subjects: Sperm whale
• Online Access: http://dx.doi.org/10.1111/j.1399-3011.1990.tb00943.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1399-3011.1990.tb00943.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1399-3011.1990.tb00943.x

The conformational free energy of armadillo metmyoglobin was examined over a pH range of 4.4–8.0 and a guanidinium chloride concentration of 0–2.3 M. For isothermal unfolding at 25′ essentially the same value was obtained for the conformational free energy from all the data: 27 ± 2 kJ/mol. These data suggest that the armadillo has the least stable metmyoglobin of any mammal thus far examined. The cooperativity of the unfolding with respect to denaturant is considerably less than for other mammalian myoglobins. On unfolding only three to four side chains with a pK A of 6 in the unfolded protein are protonated instead of the six found for horse and sperm whale myoglobins.