Fish fast skeletal muscle tropomyosins show species-specific thermal stability.
Tropomyosin (TM) was isolated from the fast skeletal muscle of six fish species, whose amino acid sequences of this protein have already been revealed. The thermal stability of these TMs was measured by differential scanning calorimetry (DSC) and circular dichroism (CD), while the molecular weights were measured by mass spectrometry. The results showed clear differences in thermostability among these fish TMs, though the identity of amino acid sequences was more than 93.3%. Therefore, only a few amino acid substitutions could affect the overall stability of the TM molecule. Especially, several residues located on the molecular surface were considered to be responsible for such stability difference. In contrast, the molecular weights of these TMs as measured by mass spectrometry were higher than those calculated from amino acid composition, suggesting the presence of post-translational modification(s) which could also affect their thermal stability.
Huang
Ming-Chih
MC
Laboratory of Aquatic Molecular Biology and Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
Ochiai
Yoshihiro
Y
D000595:Amino Acid Sequence; D000818:Animals; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D005399:Fishes; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000737:chemistry*; D010802:Phylogeny; D011489:Protein Denaturation / Q000235:genetics / Q000502:physiology; D011817:Rabbits; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature; D013816:Thermodynamics; D014335:Tropomyosin / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification
D014335:Tropomyosin