The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Lina Cong - One of the best experts on this subject based on the ideXlab platform.
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cal Development and Demonstration Activities
2014Co-Authors: Streptomyces Mycarofaciens, Lina Cong, Wolfgang PiepersbergAbstract:Abstract Two subclusters from Streptomyces mycarofaciens, a Midecamycin producer, were cloned and partially sequenced. One region was located at the 5 ' end of the mid polyketide synthase (PKS) genes and contained the genes midA, midB and midC. The other region was at the 3 ' end of the PKS genes and contained midK, midI and midH. Analysis of the nucleotide sequence revealed that these genes encode dTDP-glucose synthase (midA), dTDP-glucose dehydratase (midB), aminotransferase (midC), methyltransferase (midK), glycosyltransferase (midI) and an assistant gene (midH). All of these genes are involved in the biosynthesis of dTDP-D-mycaminose, the first deoxysugar of Midecamycin, and in transferring the mycaminose to the Midecamycin aglycone in S. mycarofaciens. Similar to gene pairs desVIII/desVII in S. venezuelae and tylMIII/tylMII in S. fradiae, the product of midH probably functions as an auxiliary protein required by the MidI protein for efficient glycosyltransfer in Midecamycin biosynthesis. Key words deoxysugar; dTDP-D-mycaminose; Midecamycin; Streptomyces mycarofacien
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Cloning and characterization of genes encoded in dTDP-D-mycaminose biosynthetic pathway from a Midecamycin-producing strain, Streptomyces mycarofaciens.
Acta biochimica et biophysica Sinica, 2007Co-Authors: Lina Cong, Wolfgang PiepersbergAbstract:Two subclusters from Streptomyces mycarofaciens, a Midecamycin producer, were cloned and partially sequenced. One region was located at the 5' end of the mid polyketide synthase (PKS) genes and contained the genes midA, midB and midC. The other region was at the 3' end of the PKS genes and contained midK, midI and midH. Analysis of the nucleotide sequence revealed that these genes encode dTDP-glucose synthase (midA), dTDP-glucose dehydratase (midB), aminotransferase (midC), methyltransferase (midK), glycosyltransferase (midI) and an assistant gene (midH). All of these genes are involved in the biosynthesis of dTDP-D-mycaminose, the first deoxysugar of Midecamycin, and in transferring the mycaminose to the Midecamycin aglycone in S. mycarofaciens. Similar to gene pairs desVIII/desVII in S. venezuelae and tylMIII/tylMII in S. fradiae, the product of midH probably functions as an auxiliary protein required by the MidI protein for efficient glycosyltransfer in Midecamycin biosynthesis.
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Identification of the Midecamycin biosynthetic gene cluster in Streptomyces mycarofaciens UC189B (ATCC 21454) and analysis of the enzymes for dTDP-D-mycaminose biosynthesis
2000Co-Authors: Lina CongAbstract:In dieser Arbeit wurden die folgenden Aspekte der Genetik und Biosynthese des Makrolids Midecamycin ausgearbeitet, um die Mechanismen der Makrolidzuckersynthese zu klaren und Handwerkszeuge fur die Herstellung hybrider Makrolide zu liefern. Durch sequentielles Screening einer genomischen DNA-Bank im Cosmidvektor pKU206 durch zwei homologe PCR-amplifizierte Genproben wurden zwei Regionen von insgesamt ca. 75 kb DNA isoliert, die die gewunschten Anteile des Midecamycin (mid) Genclusters enthielten. Ca. 10 kb DNA aus Cosmid Smyc-LC1 und ca. 7 kb DNA aus Smyc-LC3 wurden komplett sequenziert. Die ubrigen Regionen wurden durch partielle Sequenzierung charakterisiert, um weitere Informationen uber Struktur und Genverteilung zu erhalten. Unter den Genen wurden 10 komplette und 14 unvollstandige Leserahmen identifiziert, die fur die Midecamycin-Biosynthese notwendig sind. Die Region der Mycarose-Biosynthesegene wurde auf Smyc-LC1 gefunden. Das komplette Set der Gene fur Biosynthese und Transfer der Mycaminose wurde kloniert. Die Organisation des mid Genclusters ist ahnlich wie in andern Makroliden zu beiden Seiten der zentralen PKS Gene mit zwei gemischten Gruppen von Zucker-, Acylierungs-, Resistenz- und Regulatorgenen strukturiert. Die Genen, midC, midH, midK und midI, wurden durch heterologe Expression charakterisiert. MidC und MidH wurden als losliche Proteine in E. coli uberproduziert, jeweils in nativer und His-tag fusionierter Primarstruktur. Die ebenfalls loslichen His-tag Proteine MidK und MidI wurden nur in geringer Menge gebildet und uber Westernblot nachgewiesen. Um die postulierten Funktionen der MidH (3,4-Isomerase) und MidC (3-Aminotransferase) nachzuweisen, wurden die Produkte eines gekoppelten Enzymtests zur Umsetzung von dTDP-D-Glucose mit RmlB (4,6-Dehydratase), MidH und MidC mittles HPLC und LC-MS Techniken ausgewertet. Es wurde bestatigt, das das MidC Protein verantwortlich ist fur die Transaminierungsreaktion bei der Bildung des dTDP-Amino-6-Deoxy-D-Glucose.
C R Hutchinson - One of the best experts on this subject based on the ideXlab platform.
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A macrolide 3-O-acyltransferase gene from the Midecamycin-producing species Streptomyces mycarofaciens.
Journal of bacteriology, 1992Co-Authors: O Hara, C R HutchinsonAbstract:The Streptomyces mycarofaciens mdmB gene encodes a 3-O-acyltransferase that catalyzes the addition of acetyl and propionyl groups to position 3 of the lactone ring in 16-member macrolide antibiotics like Midecamycin and spiramycin. A putative O-methyltransferase gene (mdmC) is immediately downstream of mdmB, and both of these genes are closely linked to the mdmA Midecamycin resistance gene.
Jian Wang - One of the best experts on this subject based on the ideXlab platform.
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Universal response method for the quantitative analysis of multi-components in josamycin and Midecamycin using liquid chromatography coupled with charged aerosol detector.
Journal of pharmaceutical and biomedical analysis, 2020Co-Authors: Guijun Liu, Bingqi Zhu, Xiaojuan Ren, Jian WangAbstract:Josamycin and Midecamycin are consisted of three groups of components with different ultraviolet maximum absorption wavelengths (λmax), which are 231 nm, 280 nm and 205 nm. The quantitative analysis of all these components is challengeable due to the absence of the respective reference substances. To address this problem, universal and reliable methods were developed using high performance liquid chromatography coupled with charged aerosol detector (HPLC-CAD) for the quantitative analysis of components in josamycin and Midecamycin. The chromatographic conditions and CAD parameters setting were optimized. Subsequently, the components were identified using HPLC coupled with ion trap/time-of-flight mass spectrometry (IT/TOF MS). The developed methods were validated by assessing linearity, limit of quantitation (LOQ), accuracy, precision and robustness. Good separations were achieved for all components and the adjustment of the filter valve and power function value efficiently improved sensitivity. The developed methods were more comprehensive than current HPLC-UV method. The experimental results demonstrated good linearity with coefficients of determination (R2) greater than 0.999 in the range of 0.002-0.30 mg mL-1. The limits of detection (LOD) were ranging from 1.8 to 2.0 μg·mL-1. The intra-day and inter-day RSD values were less than 2.0 % (n = 6) and 5.6 % (n = 9) respectively. The recoveries were 95.0 %-124.0 % at the spiked concentration levels of 0.05 %, 0.50 %, 0.10 % and 2.5 % with relative standard deviations (RSDs, n = 3) lower than 2.0 %. Finally, the developed methods were successfully applied to the quantitative analysis of minor components and used main components (leucomycin A3 and Midecamycin A1) as alternative reference substance of minor components. The overall results demonstrated that the HPLC-CAD was a good alternative for the quantitative analysis of multi-components in 16-membered macrolides.
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Characterization of 28 unknown impurities in 16-membered macrolides by liquid chromatography coupled with ion trap/time-of-flight mass spectrometry.
Journal of pharmaceutical and biomedical analysis, 2020Co-Authors: Guijun Liu, Bingqi Zhu, Xiaojuan Ren, Jian WangAbstract:Abstract In terms of risk assessment, the study of the impurity profile is important to ensure the safety and effectiveness of drugs in clinical application. Sixteen-membered macrolides are produced by microbial fermentation, and many closely related substances in the product make the components and impurities complicated. In this study, methods were developed to separate and identify the impurities in three representative 16-membered macrolides (josamycin, Midecamycin and meleumycin) using a high-performance liquid chromatography coupled to high-resolution ion trap/time-of-flight mass spectrometry (IT-TOF MS). In total, 53 impurities were characterized in the positive mode of electrospray ionization, among which 28 novel impurities were found. The proposed structures of impurities were deduced based on MS/MS data, and the ultraviolet (UV) absorption behaviors of impurities were discussed. In addition to the impurities with maximum absorption wavelengths (λmax) of 231 nm and 280 nm, there was a new group of impurities with λmax of 205 nm in meleumycin, Midecamycin and josamycin.
O Hara - One of the best experts on this subject based on the ideXlab platform.
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A macrolide 3-O-acyltransferase gene from the Midecamycin-producing species Streptomyces mycarofaciens.
Journal of bacteriology, 1992Co-Authors: O Hara, C R HutchinsonAbstract:The Streptomyces mycarofaciens mdmB gene encodes a 3-O-acyltransferase that catalyzes the addition of acetyl and propionyl groups to position 3 of the lactone ring in 16-member macrolide antibiotics like Midecamycin and spiramycin. A putative O-methyltransferase gene (mdmC) is immediately downstream of mdmB, and both of these genes are closely linked to the mdmA Midecamycin resistance gene.
Wolfgang Piepersberg - One of the best experts on this subject based on the ideXlab platform.
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cal Development and Demonstration Activities
2014Co-Authors: Streptomyces Mycarofaciens, Lina Cong, Wolfgang PiepersbergAbstract:Abstract Two subclusters from Streptomyces mycarofaciens, a Midecamycin producer, were cloned and partially sequenced. One region was located at the 5 ' end of the mid polyketide synthase (PKS) genes and contained the genes midA, midB and midC. The other region was at the 3 ' end of the PKS genes and contained midK, midI and midH. Analysis of the nucleotide sequence revealed that these genes encode dTDP-glucose synthase (midA), dTDP-glucose dehydratase (midB), aminotransferase (midC), methyltransferase (midK), glycosyltransferase (midI) and an assistant gene (midH). All of these genes are involved in the biosynthesis of dTDP-D-mycaminose, the first deoxysugar of Midecamycin, and in transferring the mycaminose to the Midecamycin aglycone in S. mycarofaciens. Similar to gene pairs desVIII/desVII in S. venezuelae and tylMIII/tylMII in S. fradiae, the product of midH probably functions as an auxiliary protein required by the MidI protein for efficient glycosyltransfer in Midecamycin biosynthesis. Key words deoxysugar; dTDP-D-mycaminose; Midecamycin; Streptomyces mycarofacien
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Cloning and characterization of genes encoded in dTDP-D-mycaminose biosynthetic pathway from a Midecamycin-producing strain, Streptomyces mycarofaciens.
Acta biochimica et biophysica Sinica, 2007Co-Authors: Lina Cong, Wolfgang PiepersbergAbstract:Two subclusters from Streptomyces mycarofaciens, a Midecamycin producer, were cloned and partially sequenced. One region was located at the 5' end of the mid polyketide synthase (PKS) genes and contained the genes midA, midB and midC. The other region was at the 3' end of the PKS genes and contained midK, midI and midH. Analysis of the nucleotide sequence revealed that these genes encode dTDP-glucose synthase (midA), dTDP-glucose dehydratase (midB), aminotransferase (midC), methyltransferase (midK), glycosyltransferase (midI) and an assistant gene (midH). All of these genes are involved in the biosynthesis of dTDP-D-mycaminose, the first deoxysugar of Midecamycin, and in transferring the mycaminose to the Midecamycin aglycone in S. mycarofaciens. Similar to gene pairs desVIII/desVII in S. venezuelae and tylMIII/tylMII in S. fradiae, the product of midH probably functions as an auxiliary protein required by the MidI protein for efficient glycosyltransfer in Midecamycin biosynthesis.
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cloningandcharacterizationofgenesencodedindtdpdmycaminosebiosyntheticpathwayfromaMidecamycinproducingstrainstreptomycesmycarofaciens
2007Co-Authors: Cong Lina, Wolfgang PiepersbergAbstract:Two subclusters from Streptomyces mycarofaciens, a Midecamycin producer, were cloned and partially sequenced. One region was located at the 5' end of the mid polyketide synthase (PKS) genes and contained the genes midA, midB and midC. The other region was at the 3' end of the PKS genes and contained midK, midI and midH. Analysis of the nucleotide sequence revealed that these genes encode dTDP-glucose synthase (midA), dTDP-glucose dehydratase (midB), aminotransferase (midC), methyltransferase (midK), glycosyltransferase (midI) and an assistant gene (midH). All of these genes are involved in the biosynthesis of dTDP-D-mycaminose, the first deoxysugar of Midecamycin, and in transferring the mycaminose to the Midecamycin aglycone in S. mycarofaciens. Similar to gene pairs desVIII/desVII in S. venezuelae and tylMIII/tylMII in S. fradiae, the product of midH probably functions as an auxiliary protein required by the MidI protein for efficient glycosyltransfer in Midecamycin biosynthesis