| Project/Area Number |
10680645
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Molecular biology
|
|---|
| Research Institution | Hirosaki University |
|---|
Principal Investigator |
HIMENO Hyouta Hirosaki University, Department of Biochemistry and Biotechnology, Associate Professor, 農学生命科学部, 助教授 (80208785)
|
|---|
| Project Period (FY) |
1998 – 2000
|
| Project Status |
Completed (Fiscal Year 2000)
|
| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1998: ¥2,000,000 (Direct Cost: ¥2,000,000)
|
|---|
| Keywords | tmRNA / trans-translation / 10Sa RNA / ssrA / SmpB / tag-peptide / pseudoknot / ribosome / translation / 10 Sa RNA / transiation / RNA / small stable RNA / alanyl-CRNA synthetase / riboseme |
|---|
| Research Abstract |
To clarify the mechanism underlying selection of the ribosome stalled on a truncated mRNA and resumption of translation at a definite position, many mutations has been introduced around the mRNA domain of E.coli tmRNA.
Indeed, the first pseudoknot structure (PK1) 12 nucleotides upstream of the tag-encoding sequence is important for efficiency of trans-translation, but it does not contribute to the correct initiation of the tag-translation. We found that positions at which a single point muation caused a decrease of trans-translation efficiency were concentrated within the span of -4 to -2. Some mutations decreased the efficiency of trans-tanslation, and some shifts the initiation point of trans-translation by -1. The 86C mutant, which has substantially no trans-translation activity, retains a normal aminoacylation activity and a normal ribosome binding activity.
We also obtained a mutant lacking a trans-translation activity by introducing only one base substitution. This mutant affected the ribosome binding but not EF-Tu binding.
It was also found that a single point mutation in the tRNA domain which inactivates the trans-translation.
These mutations are expected to be a clue for the mechanism of trans-translation.
|
