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Gene Cloning and Analysis of Biosynthetic Gene of Spectinomycin
Sohng, Jae-Kyung,Oh, Tae-Jin,Liou, Kwang-Kyoung,Lee, Hei-Chan 선문대학교 첨단과학기술연구소 2001 첨단과학기술연구소 논문집 Vol.5 No.-
A biosynthetic gene cluster involved in the production of spectinomyein was cloned from Streptomyes spectabilis cosmid library with dTDP-glucose 4,6-dehydratase and amnino transferase gene probes. The DNA probes were obtained from S. speciabilis genome with primers based on consensus sequences of known enzymes using a polymerase chain reaction. One of the cloned cosmids, pSPM8, contained the homologue of the dTDP-glucose 4,6-dehydratase and amino transferase gene. The DNA sequence analysis reveals four open reading frames and one incomplete reading frame. The putative orf1 protein reveals 29% amino acid sequence homology of putative myo-inositol-2-dehydrogenase from Vibrio anguillamm. The orf2 is about 46% homologous to putative myo-inositol-1-monophosphotase of Mycobacterium leprae. The orf3 showed strong homology (67.4%) to putative export protein (spcT) from s. flavopersicus. The amino acid sequel deduced from orf4 showed a high similarity (70.8%) to a spectinomycin resistance gene (spcN) from S. flavopersicus. Expression of orf4 in E. coli BL21 showed the spectinomycin resistance.
PAN-PVDF-PEGME Blend계 고분자전해질의 전기화학적 특성
류광선,이계중,류광경,강성구,장순호,Ryu, Kwang Sun,Lee, Gye Joong,Liou, Kwang Kyoung,Kang, Seong Gu,Chang, Soon Ho 대한화학회 1999 대한화학회지 Vol.43 No.2
PAN-PVDF-PEGME 블랜드(blend)계의 고분자전해질을 만들어 전기화학적인 특성을 조사하였으며 PEGME의 첨가에 따른 물성변화를 측정하였다. PEGME가 첨가되면서 PVDF의 결정성은 감소하고, 이온 전도도는 대부분 $∼10^{-3}S/cm$의 이온전도도를 나타내므로 고분자전해질로 사용이 가능하다. 또한 이온전도도의 온도의존성으로부터 PEGME의 첨가양이 증가할수록 효과적으로 높은 이온전도도를 갖는 통로가 생겨 이온전도도가 증가하는 것으로 예상할 수 있다. SPE 2(10 wt% PEGME)에서 가장 큰 양이온 수율을 나타내고 있으며 PEGME의 양이 증가할 수록 감소하는 것을 알 수 있다. PEGME를 첨가하지 않은 SPE 1(PAN-PVDF계) 고분자전해질의 전기화학적으로 안정한 영역은 ∼4.3 V인 반면에 PEGME를 첨가한 SPE 2-4(PAN-PVDF-PEGME계) 고분자전해질은 ∼4.6 V까지 전기화학적으로 안정한 것을 알 수 있다. 또한 이 고분자전해질을 사용하여 전지를 구성하여 충방전 성능을 비교하여 보면 PEGME를 첨가함에 따라 방전 용량이 증가함을 알 수 있다. 즉 PEGME를 첨가함에 따라 이온전도도가 증대되며, 전기화학적으로 안정한 영역이 넓어질뿐만 아니라 전지구성시 방전 성능도 향상됨을 알 수 있다. The electrochemical properties of PAN-PVDF-PEGME blend polymer electrolyte system are investigated and the physical properties are also measured with varying the content of PEGME. This PEGME partially reduces the crystallinity of PVDF. The ionic conductivities of the polymer electrolytes are about $10^{-3}S/cm$, which may be applicable to a constituent of lithium secondary battery. From the temperature dependence of ionic conductivity, it is suggested that the ionic conductivity increases with the PEGME content due to the fomation of effective ion-conducting path. The cation transference number reaches its maximum value for the electrolytes (SPE 2) with 10 wt% PEGME and then decreases for further increase of PEGME contnet. The electrochemically stable range of SPE 1 (without PEGME) is about 4.3 V, but SPE 2-4 (PAN-PVDF-PEGME system) is about 4.6 V. When these polymer electrolyte are used as electrolyte in rechargeable battery and the cell performances are tested, the discharge capacity increses with the amount of PEGME. Therefore, PEGME increases the ionic conductivity, extends the electrochemical stable range, and finally improves the discharge capacity of cell adopting the electrolyte system.
( Pageni Binod Babu ),( Tae Jin Oh ),( Kwang Kyoung Liou ),( Yeo Joon Yoon ),( Jae Kyung Sohng ) 한국미생물 · 생명공학회 2008 Journal of microbiology and biotechnology Vol.18 No.1
Two sugar biosynthetic cassette plasmids were used to direct the biosynthesis of a deoxyaminosugar. The pOTBP1 plasmid containing TDP-glucose synthase (desIII), TDPglucose-4,6-dehydratase (desIV), and glycosyltransferase (desVII/desVIII) was constructed and transformed into S. venezuelae YJ003, a strain in which the entire gene cluster of desosamine biosynthesis is deleted. The expression plasmid pOTBP3 containing 4-aminotransferase (gerB) and 3,5-epimerase (orf9) was transformed again into S. venezuelae YJ003-OTBP1 to obtain S. venezuelae YJ003-OTBP3 for the production of 4-amino-4,6-dideoxy-L-glucose derivatives. The crude extracts obtained from S. venezuelae ATCC 15439, S. venezuelae YJ003, and S. venezuelae YJ003-OTBP3 were further analyzed by TLC, bioassay, HPLC, ESI/MS, LC/MS, and MS/MS. The results of our study clearly shows that S. venezuelae YJ003-OTBP3 constructs other new hybrid macrolide derivatives including 4-amino-4,6-dideoxy-L-glycosylated YC-17 (3, [M+ Na+] m/z=464.5), methymycin (4, m/z=480.5), novamethymycin (6, m/z=496.5), and pikromycin (5, m/z=536.5) from a 12-membered ring aglycon (10-deoxymethynolide, 1) and a 14-membered ring aglycon (narbonolide, 2). These results suggest a successful engineering of a deoxysugar pathway to generate novel hybrid macrolide derivatives, including deoxyaminosugar.