1996 Fiscal Year Final Research Report Summary
Structure Formation Mechanism of Helix-Type Membrane Protein
| Project/Area Number |
07458166
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Biophysics
|
|---|
| Research Institution | Tokyo University of Agriculture and Technology |
|---|
Principal Investigator |
MITAKU Shigeki Tokyo University of Agriculture and Technology Dapertment of Biotechnology Professor, 工学部, 教授 (10107542)
|
|---|
| Project Period (FY) |
1995 – 1996
|
| Keywords | Membrane protein / Molecular structure / Activation energy / Kinetics / Nonbonded interaction / Incomplete denaturation / Bacteriorhodopsin / Hydrogen bond |
|---|
| Research Abstract |
Three kinds of denaturation experiments were performed for a typical membrane protein, bacteriorhodopsin, in order to estimate the contribution of various factors to the structure formation of membrane proteins. The results were as follow : 1. Bacteriorhodopsin denatured by the addition of alcohols. In the alcohol denaturation, the tertiary structure was destroyed with the secondary structure remained intact. 2. Bacteriorhodopsin did not denature in pure hexane. However, the structure was destroyed by the addition of small amount of alcohol, indicating that the hydroxyl group is responsible for the alcohol denaturation of membrane proteins. 3. The activation energy of the thermal denaturation was estimated from the temperature dependence of the denaturation kinetic constant. The activation energy of about 40 kcal/mol corresponds to about ten hydrogen bonds in membrane. Tihs number is the half of possible hydrogen bonds between transmembrane helices. Consequently, the mechanism of the structural stability is due to the polar interactions such as hydrogen bonds and ion pairs between transmembrane helices.
|
