Method of Screening for Antimicrobial
Compounds
Warwick Ventures has available for licence a novel ATP release assay for
Aminoacyl-tRNA Synthetases and other adenylate-forming enzymes
enabling characterisation of the functions of these synthetases and to
explore their potential as drug targets. This assay is particularly suitable for
screening potential antibiotic agents which target bacterial aminoacyl
tRNA synthetase and can be used in a high-throughput format.
BACKGROUND
The search for new and improved antimicrobial agents is
key to the fight against pathogenic microbes such as
bacteria, viruses and parasites. The emergence of
widespread resistance to clinical antimicrobial agents,
perhaps most notably methicillin resistant Staphylococcus
aureus (MRSA), means that it is essential to continue to
develop new and improved antimicrobial drugs. One
essential stage in many drug development strategies is the
large-scale screening of compounds that interact with a
known biological target for their ability to modulate the
effect of the target. Many strategies exist for the
screening of potentially antimicrobial compounds based
on the evaluation of their modulating effects on several
important microbial targets.
An important strategy in the development of antibacterial
agents is linked to the inhibition of protein synthesis, as
demonstrated by the successful use of antibiotics such as
chloramphenicol, tetracycline and erythromycin. The
bacterial aminoacyl tRNA synthetase (aaRS), which
supplies protein synthesis with aminoacyl tRNAs, is
clinically-proven as demonstrated by mupirocin
(Bactroban®). However the continual development of
resistance in clinical infection to these antibiotics makes
development of new antibiotics essential in targeting
protein synthesis, as well as other functions essential for
pathogen viability. Many drugs in clinical use can
differentiate between the bacterial and mammalian aaRS
enzymes and so represent a particularly important class of
microbial targets for the development of new and
improved drugs. Mupirocin is chemically labile and so
cannot be applied systemically. It is inactive against the
causative agent of tuberculosis and can be subject to
resistance.
INVENTION
Researchers at the University of Warwick have developed
a novel continuous ATP-release assay for aaRS and other
adenylate-forming enzymes. The assay is based on the
utilisation of AP4A as a substrate and uses commercially
available reagents and apparatus. The rate of the reaction
can be monitored by the sensitive and accurate
measurement of ATP in the presence of AP4A, by either
spectrophotometry, fluorometry or bioluminescent
methods. Furthermore the relatively weak binding affinity
of AP4A to the enzyme means that compounds with weak
inhibition constants can be measured accurately. This
makes the method especially suitable for use in drug
development using fragment-based drug design
techniques and for incorporations into high-throughput
screening methods. The features of the invention include:
No product/substrate separation stage required
No mixing
No radiolabels
Fast
Cheap
May have application potential for assays of other
clinically relevant target enzymes such as those
involved in fatty acid activation, coenzyme synthesis
and RNA metabolism
The method targets multiple gene products so
reducing the chances of resistance developing.
PATENT & PUBLICATION
This Assay is the subject of a published PCT patent
application:
PCT/GB2012/052259 Methods
Antimicrobial Compounds
of
Screening
for
Adrian J. Lloyd, Nicola J. Potter, Colin W.G. Fishwick, David
I. Roper and Christopher G. Dowson (2013) 'Adenosine
Tetraphosphoadenosine Drives a Continuous ATP-Release
Assay for Catalysis by Aminoacyl-tRNA Synthetases and
other Adenylate forming Enzymes' ACS Chemical
Biology 8 (10), 2157 - 2163
CONTACT
The invention is applicable to the screening of
antimicrobial compounds.
The patent and associated intellectual property is available
for licence through Warwick Ventures Ltd.
Further information is available on request from:
Andrew.Lee@warwick.ac.uk, Warwick Ventures Ltd, Tel:
+44 (0) 24 7615 1657, or via Andrew.Lee@warwick.ac.uk