Discovery and development of new biocatalysts to efficiently access bioactive targets
Lead Research Organisation:
University of Bristol
Department Name: Chemistry
Abstract
Using an interdisciplinary approach, our ultimate goal is to produce a multiplicity of high value
biologically active compounds from simple feed-stocks by exploiting Nature's biosynthetic machinery.
The modularity of the PKS/NRPS scaffold biosynthesis together with the plethora of post assembly
modifications of tailoring enzymes offer prospects of creating novel compounds with optimized
properties and production and the focus of this proposal is the discovery and exploitation of novel
biocatalysts. Enzymes catalyze reactions with exquisite selectivity which, in general, simply cannot be
emulated using standard chemical reactions. Whilst biotransformations are commonly used for simple
resolutions (e.g. using acylases), reductions and more recently in aldol chemistry, there are a plethora
of enzyme-catalyzed transformations which have yet to be exploited for the clean and efficient
production of bioactive scaffolds. The project will begin by exploring the biocatalytic potential of
enzymes which we have recently isolated with a view to exploiting their unique capabilities in
industrially relevant processes. For example, using a combination of X-ray crystal structures, enzyme
assays and molecular modeling, we have provided evidence for a Diels-Alderase (AbyU) in the
biosynthesis of the antibiotic abyssomicin (J. Am. Chem. Soc., 2016). We will investigate both interand
intramolecular DA reactions as well as the selectivity of AbyU using substrates with the potential
of forming more than one ring (e.g. using analogues involved in the biosynthesis of the antibiotic
tetrodecamycin). Further enzymes on the abyssomicin pathway have been characterized. The
substrate specificities of these enzymes will also be explored and engineering of their active sites will
be informed by molecular modeling leading to a series of non-natural linear tetronates with potential
antibiotic activity. All new compounds will undergo screening for biological activity. Many bioactive
compounds are assembled on oxygen heterocycles, 6-membered ring tetrahydropyrans (THPs) and 5-
membered tetrahydrofurans (THFs). The selective creation of these rings via oxidation of un-activated
methyl groups in complex linear substrates would be very difficult (arguably impossible) to achieve
chemically. However exciting preliminary in vitro studies using oxygenases involved in the biosynthesis
the antibiotic mupirocin have shown that enzymes can indeed be used to selectively generate either
THFs of THPs. The mechanisms of these and other intriguing biotransformations will be elucidated and
the substrate specificities explored. The project will include protein chemistry (including structural
studies using X-ray crystallography, state-of the-art NMR and MS techniques), isolation and structure
determination of novel compounds and molecular modeling.
biologically active compounds from simple feed-stocks by exploiting Nature's biosynthetic machinery.
The modularity of the PKS/NRPS scaffold biosynthesis together with the plethora of post assembly
modifications of tailoring enzymes offer prospects of creating novel compounds with optimized
properties and production and the focus of this proposal is the discovery and exploitation of novel
biocatalysts. Enzymes catalyze reactions with exquisite selectivity which, in general, simply cannot be
emulated using standard chemical reactions. Whilst biotransformations are commonly used for simple
resolutions (e.g. using acylases), reductions and more recently in aldol chemistry, there are a plethora
of enzyme-catalyzed transformations which have yet to be exploited for the clean and efficient
production of bioactive scaffolds. The project will begin by exploring the biocatalytic potential of
enzymes which we have recently isolated with a view to exploiting their unique capabilities in
industrially relevant processes. For example, using a combination of X-ray crystal structures, enzyme
assays and molecular modeling, we have provided evidence for a Diels-Alderase (AbyU) in the
biosynthesis of the antibiotic abyssomicin (J. Am. Chem. Soc., 2016). We will investigate both interand
intramolecular DA reactions as well as the selectivity of AbyU using substrates with the potential
of forming more than one ring (e.g. using analogues involved in the biosynthesis of the antibiotic
tetrodecamycin). Further enzymes on the abyssomicin pathway have been characterized. The
substrate specificities of these enzymes will also be explored and engineering of their active sites will
be informed by molecular modeling leading to a series of non-natural linear tetronates with potential
antibiotic activity. All new compounds will undergo screening for biological activity. Many bioactive
compounds are assembled on oxygen heterocycles, 6-membered ring tetrahydropyrans (THPs) and 5-
membered tetrahydrofurans (THFs). The selective creation of these rings via oxidation of un-activated
methyl groups in complex linear substrates would be very difficult (arguably impossible) to achieve
chemically. However exciting preliminary in vitro studies using oxygenases involved in the biosynthesis
the antibiotic mupirocin have shown that enzymes can indeed be used to selectively generate either
THFs of THPs. The mechanisms of these and other intriguing biotransformations will be elucidated and
the substrate specificities explored. The project will include protein chemistry (including structural
studies using X-ray crystallography, state-of the-art NMR and MS techniques), isolation and structure
determination of novel compounds and molecular modeling.
