The Specificity of Methyl Transferases Involved in trans Mycolic Acid Biosynthesis in Mycobacterium tuberculosis and Mycobacterium smegmatis
| Autor: | B G Schroeder, C E Barry rd |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
chemistry.chemical_classification
Magnetic Resonance Spectroscopy biology Chemistry Mycobacterium smegmatis Organic Chemistry Fatty acid Methyltransferases Mycobacterium tuberculosis Nuclear magnetic resonance spectroscopy Acetates biology.organism_classification Biochemistry Mass Spectrometry Substrate Specificity Mycolic acid Cell wall Mycolic Acids Heteronuclear molecule Drug Discovery Molecular Biology Two-dimensional nuclear magnetic resonance spectroscopy |
| Zdroj: | Bioorganic Chemistry. 29:164-177 |
| ISSN: | 0045-2068 |
| DOI: | 10.1006/bioo.2001.1207 |
| Popis: | Trans mycolic acid content is directly related to cell wall fluidity and permeability in mycobacteria. Carbon-13 NMR spectroscopy of mycolic acids isolated from Mycobacterium tuberculosis (MTB) and Mycobacterium smegmatis (MSM) fed 13C-labeled precursor molecules was used to probe the biosynthetic pathways that modify mycolic acids. Heteronuclear correlation spectroscopy (HMQC) of ketomycolic acid from MTB allowed assignment of the complete 13C-NMR spectrum. Incorporation patterns from [1-13C]-acetate and [2-13C]-acetate feeding experiments suggested that the mero chain and alpha branch of mycolic acids are both synthesized by standard fatty acid biosynthetic reactions. [13C-methyl]-L-methionine was used to specifically label carbon atoms derived from the action of the methyl transferases involved in meromycolate modification. To enrich for trans mycolic acids a strain of MTB overexpressing the mma1 gene was labeled. Carbon-carbon coupling was observed in mycolate samples doubly labeled with 13C-acetate and [13C-methyl]-L-methionine and this information was used to assess positional specificity of methyl transfer. In MTB such methyl groups were found to occur exclusively on carbons derived from the 2 position of acetate, while in MSM they occurred only on carbons derived from the 1 position. These results suggest that the MSM methyltransferase MMAS-1 operates in an inverted manner to that of MTB. |
| Databáze: | OpenAIRE |
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