title: Differences in polymer formation through disulfide bonding of recombinant light meromyosin between white croaker and walleye pollack and their possible relation to species specific differences in thermal unfolding.
abstract: Fast skeletal light meromyosins (LMMs) of white croaker and walleye pollack were prepared in our expression system using Escherichia coli and determined for their polymer-forming ability and thermodynamic properties by using sodium dodecyl sulfate polyacrylamide gel electrophoresis and differential scanning calorimetry (DSC), respectively. White croaker LMM formed dimer by heating at 80 degrees C and showed only a single peak at 32.1 degrees C of temperature transition in DSC. On the other hand, walleye pollack LMM hardly formed polymer and showed four peaks at 27.7, 30.5, 35.8, and 43.9 degrees C. When Cys525 of white croaker LMM was replaced by alanine, this point-mutated LMM showed no change in its DSC profile but formed no dimer upon heating, suggesting a possible role of Cys525 in dimer formation. On the other hand, walleye pollack LMM where Cys491 was substituted by alanine changed its DSC profile, showing four peaks at 27.9, 29.1, 38.4, and 43.9 degrees C. However, this point-mutated LMM formed no dimer upon heating as in the case of native LMM. These results suggest that cysteine residue(s) participates in thermal gel formation of LMM when it locates in a suitable position of the sequence.
authors.affiliation: Laboratory of Aquatic Molecular Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Fukushima
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Yoon
authors.forename: Shugo
authors.initials: S
authors.lastname: Watabe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002152:Calorimetry, Differential Scanning; D004220:Disulfides / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D005399:Fishes; D006358:Hot Temperature; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000737:chemistry*; D015879:Myosin Subfragments / Q000737:chemistry*; D010473:Perciformes; D011108:Polymers / Q000737:chemistry*; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry; D020539:Sequence Analysis, Protein; D013045:Species Specificity; D013816:Thermodynamics
chemical_list: D004220:Disulfides; D015879:Myosin Subfragments; D011108:Polymers; D011994:Recombinant Proteins