Sang Kil Lee

Publications (6)10.8 Total impact

• Article: Hydroxylation of Indole by PikC Cytochrome P450 from Streptomyces venezuelae and Engineering Its Catalytic Activity by Site-Directed Mutagenesis

  Sang Kil Lee, Je Won Park, Sung Ryeol Park, Jong Seog Ahn, Cha Yong Choi, Yeo Joon Yoon
  Journal of Microbiology and Biotechnology 12/2006; 16(6):974. · 1.38 Impact Factor
• Source

  Available from: Jae Kyung Sohng

  Article: Heterologous expression of tylosin polyketide synthase and production of a hybrid bioactive macrolide in Streptomyces venezuelae.

  Won Seok Jung, Sang Kil Lee, Jay Sung Joong Hong, Sung Ryeol Park, Soon Jeong Jeong, Ah Reum Han, Jae Kyung Sohng, Byung Gee Kim, Cha Yong Choi, David H Sherman, Yeo Joon Yoon
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  ABSTRACT: Tylosin polyketide synthase (Tyl PKS) was heterologously expressed in an engineered strain of Streptomyces venezuelae bearing a deletion of pikromycin PKS gene cluster using two compatible low-copy plasmids, each under the control of a pikAI promoter. The mutant strain produced 0.5 mg/l of the 16-membered ring macrolactone, tylactone, after a 4-day culture, which is a considerably reduced culture period to reach the maximum production level compared to other Streptomyces hosts. To improve the production level of tylactone, several precursors for ethylmalonyl-CoA were fed to the growing medium, leading to a 2.8-fold improvement (1.4 mg/ml); however, switching the pikAI promoter to an actI promoter had no observable effect. In addition, a small amount of desosamine-glycosylated tylactone was detected from the extract of the mutant strain, revealing that the native glycosyltransferase DesVII displayed relaxed substrate specificity in accepting the 16-membered ring macrolactone to produce the glycosylated tylactone. These results demonstrate a successful attempt for a heterologous expression of Tyl PKS in S. venezuelae and introduce S. venezuelae as a rapid heterologous expression system for the production of secondary metabolites.
  Applied Microbiology and Biotechnology 11/2006; 72(4):763-9. · 3.42 Impact Factor
• Article: Neopikromycin and novapikromycin from the pikromycin biosynthetic pathway of Streptomyces venezuelae.

  Sang Kil Lee, Je Won Park, Ji Won Kim, Won Seok Jung, Sung Ryeol Park, Cha Yong Choi, Eung Soo Kim, Beom Seok Kim, Jong Seog Ahn, David H Sherman, Yeo Joon Yoon
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  ABSTRACT: Two new macrolides from the pikromycin biosynthetic pathway of Streptomyces venezuelae, neopikromycin (9) and novapikromycin (10), were identified and structurally characterized through mass spectrometry and NMR spectroscopy. The established structures showed that 9 and 10 have hydroxyl groups at C-14 (9) and at both C-12 and C-14 (10), on the basis of a comparison with narbomycin (7). The purified PikC cytochrome P450 monooxygenase catalyzes the in vitro hydroxylation of 7 and pikromycin (8) to yield 9 and 10, respectively, thus expanding the substrate- and regio-flexibility of this enzyme.
  Journal of Natural Products 06/2006; 69(5):847-9. · 3.13 Impact Factor
• Article: Identification and Antibacterial Activity of a New Oleandomycin Derivative from Streptomyces antibioticus.

  Beom Seok Kim, Hyuncheol Oh, Sun Young Kim, Jeong Ah Park, Yeo Joon Yoon, Sang Kil Lee, Bo Yeon Kim, Jong Seog Ahn
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  ABSTRACT: For Abstract see ChemInform Abstract in Full Text.
  ChemInform 08/2005; 36(39).
• Article: Identification and antibacterial activity of a new oleandomycin derivative from Streptomyces antibioticus.

  Beom Seok Kim, Hyuncheol Oh, Sun Young Kim, Jeong Ah Park, Yeo Joon Yoon, Sang Kil Lee, Bo Yeon Kim, Jong Seog Ahn
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  ABSTRACT: During the study on the oleandomycin production, we purified a new oleandomycin derivative having a macrolactone of which biosynthesis does not follow the genetic architecture of the oleandomycin PKS. The molecular formula for the compound was suggested as C35H59NO11 on the basis of the analysis of NMR and HRMS data (m/z 670.4185, Delta-1.9mmu, calcd for C35H60NO11). 13C NMR assignments and analysis of COSY, HMBC and HMQC data suggested that the compound differs from oleandomycin by formation of the olefinic functionality resulting from the dehydration of a hydroxy group in oleandomycin. The new oleandomycin derivative has antibacterial activities similar to those of oleandomycin agaisnt Enterococcus faecalis, Bacillus subtilis and Staphylococcus aureus.
  The Journal of Antibiotics 04/2005; 58(3):196-201. · 1.65 Impact Factor
• Article: The role of erythromycin C-12 hydroxylase, EryK, as a substitute for PikC hydroxylase in pikromycin biosynthesis.

  Sang Kil Lee, Devi B Basnet, Cha Yong Choi, Jae Kyung Sohng, Jong Seog Ahn, Yeo Joon Yoon
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  ABSTRACT: The substrate flexibility of the erythromycin C-12 hydroxylase from Saccharopolyspora erythraea, EryK, was investigated to test its potential for the generation of novel polyketide structures. We have shown that EryK can accept the substrates of PikC from Streptomyces venezuelae which is responsible for the hydroxylation of YC-17 and narbomycin. In a S. venezuelae pikC deletion mutant, EryK could catalyze the hydroxylation of YC-17 and narbomycin to generate methymycin/neomethymycin and pikromycin, respectively. Molecular modeling of the enzyme-substrate complex suggested the possible interaction of EryK with alternative substrates. The results indicate that EryK is flexible toward some alternative polyketides and can be useful for structural diversification of macrolides by post-polyketide synthase hydroxylation.
  Bioorganic Chemistry 01/2005; 32(6):549-59. · 1.21 Impact Factor