The Active Conformation of Avilamycin A Is Conferred by AviX12, a Radical AdoMet Enzyme
| Autor: | Gerd Hauser, Steffen J. Glaser, Thorsten Friedrich, Andreas Bechthold, Carsten Hofmann, Raija Boll, Thorsten Koslowski, Björn Heitmann |
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| Rok vydání: | 2006 |
| Předmět: |
S-Adenosylmethionine
Magnetic Resonance Spectroscopy Protein Conformation Stereochemistry Molecular Sequence Data Molecular Conformation Racemases and Epimerases Oligosaccharides Mannose Iron–sulfur cluster medicine.disease_cause Biochemistry Open Reading Frames chemistry.chemical_compound Affinity chromatography Biosynthesis Polysaccharides Proliferating Cell Nuclear Antigen Gene cluster Carbohydrate Conformation medicine Molecular Biology Escherichia coli chemistry.chemical_classification Chemistry Genetic Complementation Test Electron Spin Resonance Spectroscopy Cell Biology Aglycone Enzyme Protein Binding |
| Zdroj: | Journal of Biological Chemistry. 281:14756-14763 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m601508200 |
| Popis: | The antibiotic avilamycin A is produced by Streptomyces viridochromogenes Tü57. Avilamycin belongs to the family of orthosomycins with a linear heptasaccharide chain linked to a terminal dichloroisoeverninic acid as aglycone. The gene cluster for avilamycin biosynthesis contains 54 open reading frames. Inactivation of one of these genes, namely aviX12, led to the formation of a novel avilamycin derivative named gavibamycin N1. The structure of the new metabolite was confirmed by mass spectrometry (MS) and NMR analysis. It harbors glucose as a component of the heptasaccharide chain instead of a mannose moiety in avilamycin A. Antibacterial activity tests against a spectrum of Gram-positive organisms showed that the new derivative possesses drastically decreased biological activity in comparison to avilamycin A. Thus, AviX12 seems to be implicated in converting avilamycin to its bioactive conformation by catalyzing an unusual epimerization reaction. Sequence comparisons grouped AviX12 in the radical S-adenosylmethionine protein family. AviX12 engineered with a His tag was overexpressed in Escherichia coli and purified by affinity chromatography. The iron sulfur cluster [Fe-S] present in radical AdoMet enzymes was detected in purified AviX12 by means of electron paramagnetic resonance spectroscopy. |
| Databáze: | OpenAIRE |
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