2000 Fiscal Year Final Research Report Summary
Structural Change and Activity Control of Peptides and Proteins in Biomembranes Including Boundary Lipids
| Project/Area Number |
10660122
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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 |
食品科学・栄養科学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
MATSUMURA Yasuki KYOTO UNIVERSITY, Research Institute for Food Science Associate Prof., 食糧科学研究所, 助教授 (50181756)
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| Project Period (FY) |
1998 – 2000
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| Keywords | boundary lipids / biomembranes / proteins / enzymes / structural change / activity control |
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| Research Abstract |
Acidic phospholipids such as phophatidic acid (PA) and Phosphatidylinositol (PI) and Sphingomyelin (SpM) are believed to act as "boundary lipids" via strong interaction with proteins in biomembranes. These lipids also affect the orientation of phosphatidylcholine (PC) in biomembranes. The purpose of this project is to understand the effects of "boundary lipids" on the structure and activity of peptides and proteins in biomembranes.
In this project, lipoxygenase (LOX) was chosen as a target protein, because this enzyme is known to act at the interface of water and lipid. The effects of addition of boundary lipids on the activity of LOX at the interfaces of emulsion droplets and vesicles were investigated. The activity of LOX was increased dramatically by the addition of PA and fatty acids in vesicle dispersions as well as in emulsions. The kinetic analyses and ζ potential measurements demonstrated that the elevation of LOX activity was due to the increase of adsorptivity of LOX to interfaces through electrostatic interaction. Analyses by dynamic light scattering, electron micrograph and ^<31>P-NMR revealed that the addition of PA and fatty acids induced the formation of hexagonal structure and micellar particles from PC vesicle membranes. These results have shown that "boundary lipids" control the enzymatic activity through modification of membrane structure.
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