• 미생물학회지
• /
• 제29권3호
• /
• pp.160-166
• /
• 1991

The regulatory mechanism of tubercidin biosynthesis in Streptomyces tubercidicus was studied. In a wild type strain, addition of adenine and histidine into the medium decreased the tubercidin production by 60-65% and 40%, respectively. The effects of adenine and histidine were alleviated by the addition of inosine monophosphate and 5-aminoimidazole-4-carboxamide ribotide. The production of tubercidin in S. tubercidicus K115 strain ($ade^{-}$ ) was nearly shut off by histidine. In contrast with K115 strain, adenine inhibited the tubercidin biosynthesis in S. tubercidicus K412 strain ($his^{-}$. In S. tubercidicus F667 strain ($ade^{-}$ , $his^{-}$ ), tubercidin production was increased by adenine and histidine. From the effects of adenine and histidine on tubercidin biosynthesis in S. tubercidicus wild type and mutant strains, it became known that feedback control by adenine and histidine of biosynthetic pathwat for purine ribonucleotide and histidine are involved in the regulation of tubercidin biosynthesis.

• 미생물학회지
• /
• 제24권4호
• /
• pp.364-369
• /
• 1986

Streptomyces tuberaidicus 의 원형질체 생성, 생성된 원형질체의 정상 균사체료의 환원 그리고 원형질체 융합에 대하여 조 사하였다. 또한 균사체로부터 원형질체가 생성되는 과정을 주사전자현미경을 사용하여 관찰하였다. 원형칠체는 슐샤의 끝부위 에서 뿐만 아니라 균샤 말단의 부풀어오른 부위 그리고 균사의 중간 부위에서도 생성이되는 세 종류의 원형질체 생성양을 보였다. 원형질체의 정상균사체로의 환원률은 tryptone-yeast extract-sodium acetate-$MgCl_2-CaCl_2$-sucrose로 조성된 배 지에서 대략 17%이었으며, 이때 $Ca^{++},\;Mg^{++}$ soccrose의 농도가 각각 50mM, 5mM, 0.4-0.SM일때 최척의 환원률을 보였다. S. tµberaidicµs의 histidine과 adenine을 요구하는 두 균주의 원형질서l간의 융합에서 30% 이상의 융합빈도플 얻

• 한국미생물·생명공학회지
• /
• 제24권1호
• /
• pp.82-86
• /
• 1996

Three thousand microbial strains collected from different sources were screened for herbicidal activity. A strain of ME-9189 showed herbicidal activity against Digitaria sanguinalis and Portulaca oleracea was isolated from a mountainy soil. Based on taxonomic studies, the strain was identified as Streptomyces tubercidicus. The active compound of ME-9189 was purified from the culture broth by charcoal, silica gel, sephadex LH-20 column chromatography and crystalization, consecutively. The ME-9189 compound was identified as tubercidin by spectroscopic methods of UV, $^{1}H$ and $^{13}C$-NMR, and EIMS. In the bioassay, growth of radish shoot and root was inhibited by 50% with tubercidin treatment of 10 ppm, showing 2 times higher activity than that of herbicidin A and similar to that of toyocamycin.

• 미생물학회지
• /
• 제29권2호
• /
• pp.97-103
• /
• 1991

Glutamine phosphoribosylpyrophosphate amidotransferase of Streptomyces tubercidicus was purified and characterized. Molecular weight of the isolated enzyme was determined to be approximately 230,000 and was composed foru identical subunits having a molecular weight of 58,000. This enzyme was strongly inhibited by AMP while considerably inhibited by ATP and GTP. Inhibition effect of enzyme activity by AMP was antagonized by increased concentration of substrate, PRPP, and metal ion (especially, $Mg^{++}$) was essential in both catalytic activity and nucleotide inhibition of this enzyme. Therefore, it was confirmed that end product inhibition of glutamine phosphoribosylpyrophosphate amidotransferase by adenine participated in the regulation of tubercidin biosynthesis from Streptomyces tubercidicus.s.

• Archives of Pharmacal Research
• /
• 제21권6호
• /
• pp.692-697
• /
• 1998

GTP cyclohydrolase I catalyzing the first reaction in the biosynthesis of pterin moiety of folic acid in bacteria, was purified from Streptomyces tubercidicus by at least 203-fold with a yield of 32% to apparent homogeneity, using ammonium sulfate fractionation, DEAE-cellulose, Sepharose CL-6B, and hydroxylapatite column chromatography. The molecular weight of the native enzyme was estimated to be 230,000 daltons by gel permeation chromatography. The purified enzyme gave a single band on sodium dodesyl sulfate-polyacrylamide gel electrophoresis and its molecular weight was apparently 58,000 daltons. These results indicate that the enzyme consists of four subunits with the same molecular weight. The $K_m$ and $V_{max}$ values for GTP of the purified enzyme were determined to be 80${\mu}$M and 90nmol/min (mg protein), respectively. The optimum pH and temperature for the enzyme reaction were pH 7.5-8.5 and $40-42^{\circ}C$, respectively. Coenzyme or metal ion was not required for the enzyme activity. The enzyme activity was inhibited by most divalent cations, while it was slightly activated by potassium ion. In case of nucleotides, CTP, GMP, GDP, and UTP inhibited enzyme activity, among which GDP exhibited the strongest inhibitory effect.

• 미생물학회지
• /
• 제25권3호
• /
• pp.180-183
• /
• 1987

Type II제한효소 Stu I을 순수정제하고 그 효소적 특성을 연구하였다. 100g(we weight)의 Streptomyces tubercidicus(ATCC 25502)로부터 얻은 crude extranct를 ammonium sulfate fractionation한 후, DEAE-Sephadex(A-50), QAE-Sephadex(A-50) 그리고 Heparin-agarose의 순서로 column chromatography를 수행하여 1,2mg의 비특이성 nuclease가 없는 Stu I 제한효소를 얻었다. 이 시료에 포함되어 있는 다른 오염 단백질은 Sephadex G-100 column으로 gel filtration 하여 제거함으로써, 순수한 Stu I 단백질을 얻을 수 있었다. 정제된 Stu I 제한효소는 10% SDS-polyacrylamide gel electrophoresis 결과 한 개의 band로 나타났으며, 그 분자량은 34,000 $\pm$ 1,000 dalton이었다. 이 효소는 $Mg^{2+}$이온 존재하에 중성의 pH(7.0-8.0)에서 최대의 활성을 나타내었다. NaCl은 이 효소의 활성에는 필요하지 않았다.