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Micromonospora-produced sisomicin components
Abstract:
A sisomicin fermentation carried out in the presence of (methyl-14C)-L-methionine resulted in a crude mixture, composed of methyl-14C-labeled sisomicin as a major component; and two 4''-C-desmethylsisomicin (66-40B and 66-40D) isomer-like components, an unidentified component and a gentamicin A-like antibiotic as minor components. When (methyl-14C)-L-methionine was added in an early stage of the fermentation (24 hours), incorporation of methyl-14C-label into polar components (e.g., gentamicin A-like antibiotic) preceded that into sisomicin. Chromatographic evidence for the bioconversion of (methyl-14C)-gentamicin A to a radioactive sisomicin-like product (possibly (3''-N-methyl-14C)-sisomicin) was seen, when a Micromonospora blocked mutant was incubated in the presence of the former antibiotic.
Insights
Sisomicin fermentation using (methyl-14C)-L-methionine produced labeled sisomicin and related compounds. Gentamicin A-like compounds were formed early, suggesting a potential bioconversion pathway for sisomicin production.
Area of Science:
- Microbiology
- Biochemistry
- Antibiotic Research
Background:
- Sisomicin is an aminoglycoside antibiotic produced by fermentation.
- Understanding the biosynthetic pathway of sisomicin is crucial for optimizing its production and discovering novel analogs.
Purpose of the Study:
- To investigate the biosynthetic pathway of sisomicin using radiolabeled precursors.
- To identify potential intermediates and byproducts in sisomicin fermentation.
Main Methods:
- Fermentation of Micromonospora with (methyl-14C)-L-methionine.
- Analysis of fermentation products using chromatography.
- Bioconversion studies with a Micromonospora blocked mutant and radiolabeled gentamicin A.
Main Results:
- (methyl-14C)-L-methionine incorporation yielded labeled sisomicin, desmethylsisomicin isomers, and other minor components.
- Early addition of the label favored incorporation into polar components like gentamicin A-like antibiotics.
- Evidence suggested bioconversion of (methyl-14C)-gentamicin A to a sisomicin-like product.
Conclusions:
- The study elucidates aspects of sisomicin biosynthesis, highlighting the role of gentamicin A-like compounds.
- The findings suggest a potential pathway involving gentamicin A intermediates in sisomicin production.
- This research provides insights into aminoglycoside antibiotic biosynthesis and potential for metabolic engineering.