http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Nepal, Keshav Kumar,Oh, Tae-Jin,Sohng, Jae Kyung Springer-Verlag 2009 Molecules and cells Vol.27 No.5
<P>The 2-deoxystreptamine and paromamine are two key intermediates in kanamycin biosynthesis. In the present study, pSK-2 and pSK-7 recombinant plasmids were constructed with two combinations of genes: kanABK and kanABKF and kacA respectively from kanamycin producer Streptomyces kanamyceticus ATCC12853. These plasmids were heterologously expressed into Streptomyces lividans TK24 independently and generated two recombinant strains named S. lividans Sk-2/SL and S. lividans SK-7/SL, respectively. ESI/ MS and ESI-LC/MS analysis of the metabolite from S. lividans SK-2/SL showed that the compound had a molecular mass of 163 [M + H]+, which corresponds to that of 2-deoxystreptamine. ESI/MS and MS/MS analysis of metabolites from S. lividans SK-7/SL demonstrated the production of paromamine with a molecular mass of 324 [M + H]+. In this study, we report the production of paromamine in a heterologous host for the first time. This study will evoke to explore complete biosynthetic pathways of kanamycin and related aminoglycoside antibiotics.</P>
Genetic Engineering of Streptomyces lividans TK24 for the production of kanamycin derivatives.
Keshav Kumar Nepal,Tae-Jin Oh,Hei Chan Lee,Jae Kyung Sohng 한국당과학회 2008 한국당과학회 학술대회 Vol.2008 No.1
Kanamycins, pseudotrisaccharides antibiotics, have three closely related structural form namely kanamycin A, kanamycin B and kanamycin C in which 2-DOS is substituted at the C-4 position by an aminoglucose functionality: 6-amino-6- deoxy-D-glucose, neosamine, and D -glucosamine respectively and at the C-6 position by 3-amino-3-deoxy-D-glucose (kanosamine). Here, we have Engineered Streptomyces lividans TK24 by expressing two sets of rebombinant plasmids pSK-7 and pSK-17 responsible for the production of paromamine and kanamycin C respectively. Bio-active secondary metabolite from pSK-17/SL against Bacillus subtilis and ESI/MS,LC/MS and ESI/MS/MS at 485 [M+H]+ were the evidences for the production of Kanamycin C.
Nepal, Keshav Kumar,Oh, Tae-Jin,Subba, Bimala,Yoo, Jin Cheol,Sohng, Jae Kyung Korean Society for Molecular Biology 2009 Molecules and cells Vol.27 No.1
Amino acid homology analysis predicted that rbmD, a putative glycosyltransferase from Streptomyces ribosidificus ATCC 21294, has the highest homology with neoD in neomycin biosynthesis. S. fradiae BS1, in which the production of neomycin was abolished, was generated by disruption of the neoD gene in the neomycin producer S. fradiae. The restoration of neomycin by self complementation suggested that there was no polar effect in the mutant. In addition, S. fradiae BS6 was created with complementation by rbmD in S. fradiae BS1, and secondary metabolite analysis by ESI/MS, LC/MS and MS/MS showed the restoration of neomycin production in S. fradiae BS6. These gene inactivation and complementation studies suggested that, like neoD, rbmD functions as a 2-N-acetlyglucosaminyltransferase and demonstrated the potential for the generation of novel aminoglycoside antibiotics using glycosyltransferases in vivo.
Keshav Kumar Nepal,오태진,송재경 한국분자세포생물학회 2009 Molecules and cells Vol.27 No.5
The 2-deoxystreptamine and paromamine are two key intermediates in kanamycin biosynthesis. In the present study, pSK-2 and pSK-7 recombinant plasmids were constructed with two combinations of genes: kanABK, and kanABKF and kacA respectively from kanamycin producer Streptomyces kanamyceticus ATCC12853. These plasmids were heterologously expressed into Streptomyces lividans TK24 independently and generated two recombinant strains named S. lividans SK-2/SL and S. lividans SK-7/SL, respectively. ESI/ MS and ESI-LC/MS analysis of the metabolite from S. lividans SK-2/SL showed that the compound had a molecular mass of 163 [M + H]+, which corresponds to that of 2-deoxystreptamine. ESI/MS and MS/MS analysis of metabolites from S. lividans SK-7/SL demonstrated the production of paromamine with a molecular mass of 324 [M + H]+. In this study, we report the production of paromamine in a heterologous host for the first time. This study will evoke to explore complete biosynthetic pathways of kanamycin and related aminoglycoside antibiotics.
Keshav Kumar Nepal,오태진,Bimala Subba,유진철,송재경 한국분자세포생물학회 2009 Molecules and cells Vol.27 No.1
Amino acid homology analysis predicted that rbmD, a putative glycosyltransferase from Streptomyces ribosidificus ATCC 21294, has the highest homology with neoD in neomycin biosynthesis. S. fradiae BS1, in which the production of neomycin was abolished, was generated by disruption of the neoD gene in the neomycin producer S. fradiae. The restoration of neomycin by self complementation suggested that there was no polar effect in the mutant. In addition, S. fradiae BS6 was created with complementation by rbmD in S. fradiae BS1, and secondary metabolite analysis by ESI/MS, LC/MS and MS/MS showed the restoration of neomycin production in S. fradiae BS6. These gene inactivation and complementation studies suggested that, like neoD, rbmD functions as a 2-N-acetlyglucosaminyltransferase and demonstrated the potential for the generation of novel aminoglycoside antibiotics using glycosyltransferases in vivo.
Discovery of parallel pathways of kanamycin biosynthesis allows antibiotic manipulation
Park, Je Won,Park, Sung Ryeol,Nepal, Keshav Kumar,Han, Ah Reum,Ban, Yeon Hee,Yoo, Young Ji,Kim, Eun Ji,Kim, Eui Min,Kim, Dooil,Sohng, Jae Kyung,Yoon, Yeo Joon Nature Publishing Group, a division of Macmillan P 2011 Nature chemical biology Vol.7 No.11
Kanamycin is one of the most widely used antibiotics, yet its biosynthetic pathway remains unclear. Current proposals suggest that the kanamycin biosynthetic products are linearly related via single enzymatic transformations. To explore this system, we have reconstructed the entire biosynthetic pathway through the heterologous expression of combinations of putative biosynthetic genes from Streptomyces kanamyceticus in the non??aminoglycoside-producing Streptomyces venezuelae. Unexpectedly, we discovered that the biosynthetic pathway contains an early branch point, governed by the substrate promiscuity of a glycosyltransferase, that leads to the formation of two parallel pathways in which early intermediates are further modified. Glycosyltransferase exchange can alter flux through these two parallel pathways, and the addition of other biosynthetic enzymes can be used to synthesize known and new highly active antibiotics. These results complete our understanding of kanamycin biosynthesis and demonstrate the potential of pathway engineering for direct in vivo production of clinically useful antibiotics and more robust aminoglycosides.