Characterisation of a silent biosynthetic biosynthetic gene cluster in Streptomyces

Natural products produced by organisms are molecules that are structurally and
functionally diverse. They play an important role in modern medicine, with many
being used as treatments against diseases such as cancer and cardiovascular disease.
Many also possess antimicrobial activity and have been prescribed as antibiotics to
treat and prevent bacterial and fungal infections. Unfortunately, the last century has
seen an increase of bacteria gaining resistance against antibiotics. Paired with the slow
discovery rate of novel antibiotics, antimicrobial resistance has become a significant
problem and threatens modern medicine as routine operations and procedures become
high risks for new infections. Advancements in DNA sequencing technologies and
computational tools have uncovered a trove of silent biosynthetic gene clusters (BGCs)
in Streptomyces species. Compounds encoded by silent BGCs are not produced under
standard laboratory conditions and require manipulation through chemical and genetic
methods to activate them. This has lead to the discovery of novel products and
potential therapeutics to combat antimicrobial resistance.
The work described in this project focusses on the characterisation of a silent
BGC identified in Streptomyces. A multi-disciplinary approach was
adopted to probe the BGC. A multi-disciplinary approach was adopted to identify the
function of enzymes and proteins, ranging from computational analysis to biochemical
characterisation in vitro and in vivo. Confirmation of enzyme function led to insights
about compound structure and growth conditions were identified where the BGC
was transcriptionally active and enabled attempts for production, purification, and
functional characterisation of the compound. This approach informed about various
aspects of natural product biosynthesis, revealing an enzyme class present that is
responsible for a rare amino acid derivative and identifying substrates of multiple
biosynthetic enzymes, which in turn yielded structural insights of the mature compound,
which will aid in identification and purification