2005 Fiscal Year Final Research Report Summary
A functional site of the essential light chain involved in the regulation of filament assembly of smooth muscle myosin.
| Project/Area Number |
16570130
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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 |
Biophysics
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| Research Institution | Asahikawa Medical College |
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Principal Investigator |
KATOH Tsuyoshi Asahikawa Med.Col., Dept.Biochem., Associate Prof., 医学部, 助教授 (60194833)
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| Co-Investigator(Kenkyū-buntansha) |
TANIGUCHI Takanobu Asahikawa Med.Col., Dept.Biochem., Professor, 医学部, 教授 (60217130)
TAKEUCHI Masayuki Asahikawa Med.Col., Dept.Biochem., Assistant Prof., 医学部, 助手 (40226999)
ISHIDA Atsuhiko Asahikawa Med.Col., Dept.Biochem., Assistant Prof., 医学部, 助手 (90212886)
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| Project Period (FY) |
2004 – 2005
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| Keywords | smooth muscle myosin / conformational transition / filament assembly / phosphorylation-dependent regulatio / essential light chain / 4 domains of essential light chain / chimeric essential light chain / porcine aorta smooth muscle |
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| Research Abstract |
In order to investigate a functional region in the essential light chain (ELC) and its property for the regulation of the filament assembly of vertebrate smooth muscle myosin, we prepared chimeric ELCs in which one or two of the four helix-loop-helix domains of chicken gizzard smooth muscle myosin ELC were substituted by the corresponding domains of scallop adductor muscle myosin ELC using bacterial expression system and introduced to porcine aorta smooth muscle myosin. Examining their conformation demonstrates an importance of the 2nd domain of ELC in the formation of 10S conformation leading to the filament disassembly of unphosphorylated myosin.
To restrict the functional region into a shorter segment, we next prepared new mutant ELCs in which one of the residues 43-46,56-58, and 72-78 of chicken gizzard ELC was substituted by the corresponding residues of scallop ELC. Experiments similar to the above ones demonstrated that the residues 72-78 plays an important role in the formation of the 10S conformation of smooth myosin.
The orientation of the side chains of residues 72-78 in the 3D structure of myosin molecule indicates residues 72-77 interact with the other part of the ELC itself and residues 78-81 are exposed and able to possibly interact with the other subunit in the molecule. To examine which of parts or both is important for the formation of the 10S conformation, we then prepared other mutant ELCs in which one of the residues 72-77 and 78-81 of chicken gizzard ELC was substituted by the corresponding residues of scallop ELC. The effects of the substitutions on the formation of the 10S conformation are examining at present.
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