2001 Fiscal Year Final Research Report Summary
Studies on structure and urea-resistibility of myosin from marine elasmobranchs.
| Project/Area Number |
11660203
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fisheries chemistry
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| Research Institution | Mie University |
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Principal Investigator |
SATOSHI Kanoh Mie University, Faculty of Bioresources, Professor, 生物資源学部, 教授 (80177550)
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| Project Period (FY) |
1999 – 2001
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| Keywords | requiem shark / myosin / urea-resistibility / amino acid sequence / base sequence / primary structure / protein / cloning |
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| Research Abstract |
Objective
Elasmobranch contain urea, in the range of 0.3 to 0.6 M to exert resistancy against high osmolarity of seawater. However, proteins in urea-containing elasmobranch can maintain their physiological functions even in the presence of urea as proteins of teleost in the absence of urea. The objective of this study was to analyze the mechanism underlying urea-resistibility of requiem shark myosin.
Project
1 We examined the actin-activated Mg^<2+> - ATPase activity to probe a possible role of actin in producing urea-resistibility for shark myosin. It was assumed that the interaction between actin and myosin may stabilize the structure of shark myosin. (Kanoh et al, 1999)
2 Myosin, rod and S1 preparations from requiem shark showed decreased α-helical contents with increasing urea concentrations. However, rod was most stable against urea treatment. Furthermore, α-helical structure were completely refolded when urea was removed from the sample solutions, demonstrating their high urea-resistibility.(Kanoh et al., 2000)
3 Surface hydrophobicity of shark myosin is more resistant to urea treatments than carp myosin, and that the region connecting S1 and rod is most responsible for such differences between requiem shark and carp myosins. (Kanoh et al., 2000)
4 The regulatory mechanisms to compensate for the undesirable effects of urea at high concentrations are related to developing protein structures that are resistant to urea, at least in the case of myofibrillar ATPase in marine elasmobranch. (Kanoh et al, 2001)
5 The amino acid sequence of myosin heavy chain and three types of A1, A2 and DTNB light chains were deduced from cDNA nucleotide sequences, predicting 1937, 193, 150 and 168 amino acid residues respectively. The amino acid sequence of heavy chain showed high identity(85 %) with those from homeotherm rather than from fishes and was characteristic at 686-693, 788-794, 885-895 and 983-988. (Kanoh et al., 2002)
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