1987 Fiscal Year Final Research Report Summary
Bioorganic Chemical Studies on the Formation Mechanisms of Bioactic C-P Compounds
| Project/Area Number |
61470133
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
製造化学・食品
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| Research Institution | University of Tokyo |
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Principal Investigator |
SETO Haruo (Professor) Institute of Applied Microbiology, Univ. of Tokyo, 応用微生物研究所, 教授 (10013335)
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| Co-Investigator(Kenkyū-buntansha) |
IKEDA Keiji (Assistant) Institute of Applied Microbiology, Univ. of Tokyo, 応用微生物研究所, 教務職員 (50092127)
NAKAYAMA Hiroshi (Assistant Professor) Institute of Applied Microbiology, Univ. of Tokyo, 応用微生物研究所, 助手 (30155890)
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| Project Period (FY) |
1986 – 1987
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| Keywords | 2-phosphinomethylmalic acid / monofluoro acetic acid / PMM synthase / C-P compounds / bialaphos / ビアラホス / PMMシンターゼ |
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| Research Abstract |
This reseach has been made in order to reveal the formation mechanism of the C-P bond found in some microbial metabolites. As a target of this research we have selected a herbicide named bialaphos which contains a unique C-P-C bond. This metabolite is produced by Streptomyces hygroscopicus SF1293.
At first, the transformation mechanism of phosphimopyruvic acid (an analog of oxalacetic acid) to demethylphosphinothricin (an analog of glutamic acid) resulting in the increase of one carbor unit of the skeleton was studied by using enzyme inhibitors of TCA cycle. Addition of monofluoro acetic acid caused the accumulation of a new phosphinic acid named 2-phosphinomethylmalic acid (PMM) which was isolated by ion exchange resin cellulose chromatograpgy and gel filtration. Its structure was determined to be an analog of citric acid by ^+H- and ^<13>C-NMR spectral analysis. The absolute stereochemistry of PMM was established to be (R) by comparing with the (S)-form isomer prepared by the use of porcine heart citrate synthase.
The enzyme catalyzing this reaction was named PMM synthase and was purified to a pure protein by several chromatographic procedures. It is a homodimer consisting of 48K monomers. The N-terminal amino acid sequence up to 28 amino acids was determined. The corresponding open reading frame was found in the already cloned DNA which codes for the biosynthetic genes of bialaphos. The properties of this enzyme clearly shows that PMM synthase is very closely related to (R)-citrate synthase obtained from some anaerobic bacteria.
PMM was converted to demethylphosphinothricin (<alpha>-ketoglutaric acid analog) by aconitase and isocitrate dehydrogenase; this finding suggests strongly that TCA cycle enzymes are involved in the biosynthesis of bialaphos. Thus, the detailed mechanism of bialaphos operating in the later stage has been revealed by this research work.
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