Thermal denaturation profiles of tuna myoglobin.
Myoglobin (Mb) purified from fast skeletal muscle of bluefin tuna Thunnus thynnus orientalis was subjected to thermal treatment, and the denaturation profiles were examined by thermodynamic analysis. Based on the ellipticity or helical content obtained by circular dichroism (CD) spectrometry, it was found that denaturation of tuna Mb consisted of three steps, and that slight structural changes of Mb started below 20 degrees C. However, major structural changes were observed at around 58 and 72 degrees C. Differential scanning calorimetry (DSC) analysis revealed a similar but somewhat different thermal denaturation profile of Mb. In comparison with the denaturing profiles of whale Mb under the same conditions, the thermal stability of tuna Mb was found to be much lower. In the modeled tertiary structures of these Mbs, they were roughly similar to each other, though minor conformational differences were recognized and the total energy was found to be lower for tuna Mb.
Ochiai
Yoshihiro
Y
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan. aochiai@mail.ecc.u-tokyo.ac.jp
Watanabe
Yoshiaki
Y
Ozawa
Hideo
H
Ikegami
Shigeru
S
Uchida
Naoyuki
N
Watabe
Shugo
S
D000595:Amino Acid Sequence; D000818:Animals; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal; D009211:Myoglobin / Q000737:chemistry*; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D013696:Temperature; D013816:Thermodynamics; D014413:Tuna
D009211:Myoglobin