Methyltransferases of gentamicin biosynthesis

Area of Science:

• Microbiology
• Biochemistry
• Synthetic Biology

Background:

• Gentamicin C complex, derived from Micromonospora echinospora, is a crucial antibiotic with ongoing interest in developing analogs with enhanced therapeutic profiles.
• The complex comprises five components distinguished by varying methylation patterns, necessitating a deep understanding of their biosynthetic pathways.

Purpose of the Study:

• To elucidate the enzymatic mechanisms and genetic basis governing the methylation patterns within the gentamicin C complex.
• To identify novel enzymes involved in gentamicin biosynthesis and explore their potential for targeted production of specific gentamicin components.

Main Methods:

• Utilized gene deletion and chemical complementation strategies to dissect the gentamicin biosynthetic pathway.
• Employed whole-genome sequencing to identify previously uncharacterized enzymes, including those located outside the primary biosynthetic gene cluster.

Main Results:

• Demonstrated that methyltransferases GenN, GenD1, and GenK define the gentamicin pathway up to the branch point, forming an intricate methylation network with ectopic modification of early intermediates.
• Discovered a novel, chromosomally distant 6'-N-methyltransferase essential for producing gentamicin C2b and C1, completing the understanding of the methylation patterns.

Conclusions:

• The identified methylation network and novel enzyme fully explain the observed methylation patterns in gentamicins.
• These findings pave the way for the targeted fermentation and production of individual gentamicin components, serving as precursors for advanced semisynthetic antibiotic development.