| Project/Area Number |
05454156
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
General medical chemistry
|
|---|
| Research Institution | Chiba University |
|---|
Principal Investigator |
TATIBANA Masamiti Chiba University School of Medicine, Professor, 医学部, 教授 (50009081)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SONODA Tomoko Chiba University School of Medicine, Research Associate, 医学部, 教務職員 (20143307)
ISHIZUKA Toshiharu Chiba University School of Medicine, Assistant, 医学部, 助手 (50232294)
ISHIJIMA Sumio Chiba University School of Medicine, Assistant, 医学部, 助手 (70184520)
SUZUKI Nobuo Chiba University School of Medicine, Assistant Professor, 医学部, 助教授 (90111426)
|
|---|
| Project Period (FY) |
1993 – 1995
|
| Project Status |
Completed (Fiscal Year 1995)
|
| Budget Amount *help |
¥6,400,000 (Direct Cost: ¥6,400,000)
Fiscal Year 1995: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1993: ¥2,900,000 (Direct Cost: ¥2,900,000)
|
|---|
| Keywords | Phosphoribosylpyro-phosphate synthetase / Nucleic acid precursors / Binding protein / Regulatory protein / Molecular interaction / Complex / Rat liver enzyme / 融合タンパク質 / 分子接触部位 |
|---|
| Research Abstract |
The rat liver phosphoribosylpyrophosphate (PRPP) synthetase exists as complex aggregates composed of two kinds of 34-kDa catalytic subunits (PRS I and II) and other 39- and 41-kDa proteins, which are termed PRPP synthetase-associated proteins (PAPs). We have cloned the cDNA for the major one of 39 kDa (PAP39) from a rat liver cDNA library. Nucleotide sequencing showed that the clone encoded 356 amino acids containing sequences of all 5 peptides derived from PAP39. The deduced amino acid sequence is markedly similar to those of the 34-kDa catalytic subunits (317 residues). Excluding two totally dissimilar regions (about 45 residues), PAP39 has a 48% and 49% identities with PRS I and II,respectively. Evidence for molecular interaction of PAP39 with the catalytic subunits was obtained in cross-linking experiments using dimethyl-suberimidate on the rat liver enzyme. Furthermore, specific rabbit antibody against PAP39 completely precipitated the enzyme activity from solution, indicating that all the catalytic subunits existed as complexes containing PAP39. When PAPs were eliminated from the rat liver enzyme complex by gel filtration in the presence of 1 M M_gCl_2, alyotrope, or by mild tryptic digestion, the enzyme activity of the remaining catalytic subunits increased. Recombinant PAP39 produced as a fusion protein with glutathione S-transferase in Escherichia coli inhibited the catalytic activity of PRS I.Based on these results, we propose that PAP39, the major component of PAPs, plays a negative regulatory role in PRPP synthesis and is an important factor controlling nucleotide syntheses in mammalian tissues.
|
