1999 Fiscal Year Final Research Report Summary
Is the Quinol oxidoreductase a b/Rieske-type one in photosynthetic green sulfur bacteria?
| Project/Area Number |
10640631
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
植物生理
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
OH-OKA Hirogo Graduate School of Science, Osaka University Research Associate, 大学院・理学研究科, 助手 (30201966)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Keywords | Green Sulfur Bacteria / Photosynthetic Reaction Center / cytochrome c / Quinol Oxidoreductase / Electron Transfer / Heliobacteria |
|---|
| Research Abstract |
First of all, we searched cytochrome c1-like protein in green sulfur bacteria. After solubilization of membranes and the subsequent ion-exchange chromatography and SDS-PAGE analysis combined with heme staining, we got crude fraction containing cytochrome c1-like protein. However, its N-terminal amino acid might be blocked. We need a different strategy in the future, that is now under consideration.
Secondly, we studied the electron transfer pathway in heliobacteria. Heliobacteria are gram positive bacteria, whose reaction center (RC) is classified as a type 1. However, it has been unclear whether the RC contains membrane-bound cytochrome c (cyt c) which donates electrons to P798 as well as FィイD2AィエD2/FィイD2BィエD2 protein on the acceptor side. we analyzed the reaction mechanism on the donor side with intact cells and membranes of Heliobacterium gestii. P798ィイD1+ィエD1, immediately formed after flash excitation, was rereduced in two phases with tィイD21/2ィエD2=3 and 7 ms, respectively. The fast phase was attributable to the electron transfer from cyt c to P798, and the slow one was considered as the back reaction. Since the reaction rate from cyt c to P798 was much faster in the case of in vivo (tィイD21/2ィエD2=100μs), we have studied the effect of ion strength and/or temperature.
|
