Functional Analysis of Rat Acidic Calponin.
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- Fujii Toshihiro
- Department of Kansei Engineering, Faculty of Textile Science and Technology, Shinshu University
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- Yabe Sachiko
- Department of Kansei Engineering, Faculty of Textile Science and Technology, Shinshu University
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- Nakamura Kouta
- Department of Kansei Engineering, Faculty of Textile Science and Technology, Shinshu University
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- Koizumi Youichi
- Department of Kansei Engineering, Faculty of Textile Science and Technology, Shinshu University
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Abstract
Recombinant acidic calponin, a member of the calponin family, interacted with F-actin, but not with microtubules, desmin filaments, tropomyosin, calmodulin, S100 and phosphatidylserine (PS) vesicles with significant affinity. The bindings of acidic calponin to F-actin occurred in a concentration-dependent manner and were saturated at a molar ratio of about 1 acidic calponin to 1—2 actin molecules. The apparent Kd value of acidic calponin to F-actin was calculated to be 1.6×105 M−1. Chemical cross-linking experiments indicated that a 1 : 1 molar covalent complex of acidic calponin and actin monomer was produced as in the case of basic calponin–actin binding. No significant morphologic change of F-actin was observed by the addition of acidic calponin. Acidic calponin had little effect on actomyosin Mg2+-ATPase activity unlike basic calponin. Basic calponin partially competed with acidic calponin for binding to F-actin. Domain mapping with V8 protease revealed that acidic calponin binding site resided within the C-terminal 16 kDa fragment of actin, where the binding of basic calponin also occurs. However, both calponins showed reversal effects on fluorescence intensity of pyrene-labeled F-actin. Fragments of acidic calponin with 30 and 22 kDa, lacking the C-terminal acidic tail, were bound to F-actin. Interestingly, both the fragments became bound to PS vesicles, but not to other components. Circular dichroism studies showed that limited digestion of acidic calponin resulted in about 30% decrease of α-helix and β contents. The present results suggest that acidic calponin is functionally distinct from basic calponin and expresses a novel characteristic after removal of the acidic tail region.
Journal
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- Biological and Pharmaceutical Bulletin
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Biological and Pharmaceutical Bulletin 25 (5), 573-579, 2002
The Pharmaceutical Society of Japan
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Details 詳細情報について
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- CRID
- 1390001204627802496
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- NII Article ID
- 110003638717
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- NII Book ID
- AA10885497
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- COI
- 1:CAS:528:DC%2BD38Xkslyrtbo%3D
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- ISSN
- 13475215
- 09186158
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- NDL BIB ID
- 6154921
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- PubMed
- 12033495
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- Text Lang
- en
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- Data Source
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- JaLC
- NDL
- Crossref
- PubMed
- CiNii Articles
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- Abstract License Flag
- Disallowed