Phosphinic acids as inhibitors of D-Ala-D-Ala adding enzyme
Phosphinic acids as inhibitors of D-Ala-D-Ala adding enzyme
Bacterial drug resistance is a serious problem facing public health. There is therefore a continuing need for the development of new antibiotics. Inhibition of bacterial peptidoglycan biosynthesis is a good target for antibacterial agents as no equivalent structure exists in mammalian cells.
The final step in the cytoplasmic stage of peptidoglycan biosynthesis is catalysed by D-Ala-D-Ala adding enzyme. The enzyme is an ATP dependent ligase enzyme that catalyses the peptide bond formation between the dipedtide D-Ala-D-Ala (21) and UDPMurNAc-L-Ala-γ-D-Glu-m-DAP(20) to give the final cytoplasmic precursor to peptidoglycan UDPMurNAc-pentapeptide (22). The murF gene encoding for this enzyme has been cloned and overexpressed in Escherichia coli allowing rapid purification of large amounts of the enzyme. There are no published inhibitors for this enzyme and it is therefore a potential target for novel antibacterial agents.
The reaction catalysed by this enzyme is proposed to proceed by phosphorylation of the C-terminus of UDPMurNAc-tripeptide (20) followed by attack by the amino group of D-Ala-D-Ala forming a tetrahedral transition state that collapses to give the product (22). A phosphinic acid (42) was designed as a mimic of this transition state in the hope that it would be a potent inhibitor of the enzyme. Synthesis of (42) was not achieved but four very similar phosphinic acids (111), (128), (129) and (131) were synthesised and tested as inhibitors of D-Ala-D-Ala adding enzyme.
The N-benzyloxycarbonyl substituted phosphinic acid (131) was not an inhibitor of D-Ala-D-Ala adding enzyme but (111), (128) and (129) were. Use of a colorimetric phosphate release assay gave K1 values ranging from 200-700μM for these compounds. These are the most potent inhibitors of D-Ala-D-Ala adding enzyme prepared to date, but inclusion of more of the UDPMurNAc-tripeptide (20) in the phosphinic acid structure would appear to be required for truly potent inhibition of the enzyme. None of the compounds showed any antibacterial activity in vitro.
University of Southampton
Miller, David James
93ea59ae-757a-423b-9fcd-fa623d870465
1997
Miller, David James
93ea59ae-757a-423b-9fcd-fa623d870465
Miller, David James
(1997)
Phosphinic acids as inhibitors of D-Ala-D-Ala adding enzyme.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Bacterial drug resistance is a serious problem facing public health. There is therefore a continuing need for the development of new antibiotics. Inhibition of bacterial peptidoglycan biosynthesis is a good target for antibacterial agents as no equivalent structure exists in mammalian cells.
The final step in the cytoplasmic stage of peptidoglycan biosynthesis is catalysed by D-Ala-D-Ala adding enzyme. The enzyme is an ATP dependent ligase enzyme that catalyses the peptide bond formation between the dipedtide D-Ala-D-Ala (21) and UDPMurNAc-L-Ala-γ-D-Glu-m-DAP(20) to give the final cytoplasmic precursor to peptidoglycan UDPMurNAc-pentapeptide (22). The murF gene encoding for this enzyme has been cloned and overexpressed in Escherichia coli allowing rapid purification of large amounts of the enzyme. There are no published inhibitors for this enzyme and it is therefore a potential target for novel antibacterial agents.
The reaction catalysed by this enzyme is proposed to proceed by phosphorylation of the C-terminus of UDPMurNAc-tripeptide (20) followed by attack by the amino group of D-Ala-D-Ala forming a tetrahedral transition state that collapses to give the product (22). A phosphinic acid (42) was designed as a mimic of this transition state in the hope that it would be a potent inhibitor of the enzyme. Synthesis of (42) was not achieved but four very similar phosphinic acids (111), (128), (129) and (131) were synthesised and tested as inhibitors of D-Ala-D-Ala adding enzyme.
The N-benzyloxycarbonyl substituted phosphinic acid (131) was not an inhibitor of D-Ala-D-Ala adding enzyme but (111), (128) and (129) were. Use of a colorimetric phosphate release assay gave K1 values ranging from 200-700μM for these compounds. These are the most potent inhibitors of D-Ala-D-Ala adding enzyme prepared to date, but inclusion of more of the UDPMurNAc-tripeptide (20) in the phosphinic acid structure would appear to be required for truly potent inhibition of the enzyme. None of the compounds showed any antibacterial activity in vitro.
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Published date: 1997
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Local EPrints ID: 463122
URI: http://eprints.soton.ac.uk/id/eprint/463122
PURE UUID: 7e3ade26-cdc8-4c44-b79a-b5029db9563e
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Date deposited: 04 Jul 2022 20:45
Last modified: 23 Jul 2022 01:09
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Author:
David James Miller
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