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Antibiotic resistance represents one of the biggest public health challenges in the last few years. Mur ligases (MurC–MurF) are involved in the synthesis of ...UDP-N-acetylmuramyl-pentapeptide, the main building block of bacterial peptidoglycan polymer. They are essential for the survival of bacteria and therefore important antibacterial targets. We report herein the synthesis and structure–activity relationships of Mur ligases inhibitors with an azastilbene scaffold. Several compounds showed promising inhibitory potencies against multiple ligases and one compound also possessed moderate antibacterial activity. These results represent a solid ground for further development and optimization of structurally novel antimicrobial agents to combat the rising bacterial resistance.
•A novel antimicrobial peptide FGMp11 derived from fermented goat milk.•FGMp11 is characterized as a highly hydrophobic AMP with a β-turn structure.•The caused irreversible membrane damage and cell ...wall deformation in S. aureus.•FGMp11 inhibited S. aureus growth via hydrogen bonding and hydrophobic interactions with Mur ligase.•Electrostatic binding sites of FGMp11 to the key amino acids GLN, LEU and PRO are mainly -OH, -NH2 and -C=O groups.
Hydrophobic peptides have received considerable attention in food preservation. The elucidation of the hydrophobic points of hydrophobic peptides is helpful in revealing the antimicrobial mechanism, and screening strategies for novel antimicrobials such as molecular docking and deep learning. A novel antimicrobial peptide (AMP) FGMp11 was identified and screened from fermented goat milk with strong hydrophobic properties, β-turn structure, and the amino acid sequence of TPVVVPPFLQP. The hydrophobic properties of FGMP11 could significantly damage the integrity of the cell membrane, resulting in changes in cell morphology. Hydrophobic interactions of FGMp11 with Mur enzymes (MurC, MurD, MurE, MurF, and MurG) are ideal targets for antimicrobial therapy, as these targets are involved in peptidoglycan synthesis via hydrogen bond interactions. The electrostatic binding sites of FGMp11 and the key amino acids GLN, LEU, PRO, and VAL were mainly -OH, -NH2, and -C=O groups, reducing cell activity. FGMp11 was able to significantly inhibit the growth of S. aureus during the storage of pasteurized milk. Overall, these findings provide a scientific basis for the antimicrobial activity of FGMp11 against food-borne pathogens and its application in food preservation.
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The emergence of Multidrug Resistance (MDR) strains of bacteria has accelerated the search for new antibacterials. The specific bacterial peptidoglycan biosynthetic pathway represents opportunities ...for the development of novel antibacterial agents. Among the enzymes involved, Mur ligases, described herein, and especially the amide ligases MurC-F are key targets for the discovery of multi-inhibitors, as they share common active sites and structural features.
Sporulation during Clostridioides difficile infection (CDI) contributes to recurrent disease. Cell division and sporulation both require peptidoglycan biosynthesis. We show C. difficile growth and ...sporulation is attenuated by antisenses to murA and murC or the MurA inhibitor fosfomycin. Thus, targeting the early steps of peptidoglycan biosynthesis might reduce the onset of recurrent CDI.
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•Early stage cell wall synthesis is essential for vegetative cells and sporogenesis.•MurA and MurC catalyzes the first and third steps in cell wall synthesis.•Growth and sporogenesis were affected by genetic knockdown of murA and murC genes.•Sporogenesis was inhibited by the antibiotic fosfomycin, targeting MurA.•Recurrent C. difficile infection is linked to survival of endogenous spores.
The synthesis of the peptide stem of bacterial peptidoglycan involves four enzymes, the Mur ligases (MurC, D, E and F). Among them, MurD is responsible for the ATP-dependent addition of
-glutamic ...acid to UDP-MurNAc-
-Ala, a reaction which involves acyl-phosphate and tetrahedral intermediates. Like most enzymes of peptidoglycan biosynthesis, MurD constitutes an attractive target for the design and synthesis of new antibacterial agents.
MurD has been the first Mur ligase for which the tridimensional (3D) structure was solved. Thereafter, several co-crystal structures with different ligands or inhibitors were released. In the present review, we will deal with work performed on substrate specificity, reaction mechanism and 3D structure of
MurD. Then, a part of the review will be devoted to recent work on MurD orthologs from species other than
and to cellular organization of Mur ligases and
regulation of the MurD activity. Finally, we will review the different classes of MurD inhibitors that have been designed and assayed to date with the hope of obtaining new antibacterial compounds.
Mur ligases participate in the intracellular path of bacterial peptidoglycan biosynthesis and constitute attractive, although so far underexploited, targets for antibacterial drug discovery. A series ...of hydroxy‐substituted 5‐benzylidenethiazolidin‐4‐ones were synthesized and tested as inhibitors of Mur ligases. The most potent compound 5 a was active against MurD–F with IC50 values between 2 and 6 μm, making it a promising multitarget inhibitor of Mur ligases. Antibacterial activity against different strains, inhibitory activity against protein kinases, mutagenicity and genotoxicity of 5 a were also investigated, and kinetic and NMR studies were conducted.
Multiple inhibitors of MurD–F: Mur ligases—key enzymes in the intracellular path of peptidoglycan biosynthesis—are vital for the survival of bacteria and represent promising targets for antibacterial drug discovery. Hydroxy‐substituted 5‐benzylidenethiazolidin‐4‐ones were synthesized and evaluated. They were found to be inhibitors of multiple MurD–F ligases with weak antibacterial activity.
The ATP-dependent Mur ligases (MurC, MurD, MurE and MurF) successively add
l-Ala,
d-Glu,
meso-A
2pm or
l-Lys, and
d-Ala-
d-Ala to the nucleotide precursor UDP-Mur
NAc, and they represent promising ...targets for antibacterial drug discovery. We have used the molecular docking programme eHiTS for the virtual screening of 1990 compounds from the National Cancer Institute ‘Diversity Set’ on MurD and MurF. The 50 top-scoring compounds from screening on each enzyme were selected for experimental biochemical evaluation. Our approach of virtual screening and subsequent in vitro biochemical evaluation of the best ranked compounds has provided four novel MurD inhibitors (best IC
50
=
10
μM) and one novel MurF inhibitor (IC
50
=
63
μM).
The Mur ligases (MurC, MurD, MurE and MurF) catalyze the stepwise synthesis of the UDP-
N-acetylmuramoyl-pentapeptide precursor of peptidoglycan. The
murC,
murD,
murE and
murF genes from
...Staphylococcus aureus, a major pathogen, were cloned and the corresponding proteins were overproduced in
Escherichia coli and purified as His
6-tagged forms. Their biochemical properties were investigated and compared to those of the
E. coli enzymes. Staphylococcal MurC accepted
l-Ala,
l-Ser and Gly as substrates, as the
E. coli enzyme does, with a strong preference for
l-Ala.
S. aureus MurE was very specific for
l-lysine and in particular did not accept
meso-diaminopimelic acid as a substrate. This mirrors the
E. coli MurE specificity, for which
meso-diaminopimelic acid is the preferred substrate and
l-lysine a very poor one.
S. aureus MurF appeared less specific and accepted both forms (
l-lysine and
meso-diaminopimelic acid) of UDP-MurNAc-tripeptide, as the
E. coli MurF does. The inverse and strict substrate specificities of the two MurE orthologues is thus responsible for the presence of exclusively
meso-diaminopimelic acid and
l-lysine at the third position of the peptide in the peptidoglycans of
E. coli and
S. aureus, respectively. The specific activities of the four Mur ligases were also determined in crude extracts of
S. aureus and compared to cell requirements for peptidoglycan biosynthesis.
The widespread emergence of pathogenic bacterial strains with resistance to antibiotics is becoming a serious threat to public health. Continuous development of novel antibacterials therefore remains ...one of the biggest challenges to science and unmet needs in the clinics. The biosynthetic pathway of bacterial peptidoglycan, an essential building block of cell walls, has been well studied and appears to be a rich source of attractive enzyme targets for new antibacterials. We have therefore reviewed the intracellular part of peptidoglycan biosynthesis, including the enzymes GlmS, GlmM, GlmU for formation of UDP-GlcNAc, subsequent pentapeptide synthesis by MurA-MurF, and its connection to lipid carrier by MraY and MurG. Naturally occurring inhibitors and the development of low-molecular weight inhibitors of the intracellular part of peptidoglycan synthesis are presented.
Chlamydiaceae
are obligate intracellular bacteria that do not synthesise detectable peptidoglycan although they possess an almost complete arsenal of genes encoding peptidoglycan biosynthetic ...activities. In this paper, the
murF
gene from
Chlamydia trachomatis
was shown to be capable of complementing a conditional
Escherichia coli
mutant impaired in UDP-MurNAc-tripeptide:
d
-Ala-
d
-Ala ligase activity. Recombinant MurF from
C. trachomatis
was overproduced and purified from
E. coli
. It exhibited ATP-dependent UDP-MurNAc-X-γ-
d
-Glu-
meso
-A
2
pm:
d
-Ala-
d
-Ala ligase activity in vitro. No significant difference of kinetic parameters was seen when X was
l
-Ala,
l
-Ser or Gly. The
l
-Lys-containing UDP-MurNAc-tripeptide was a poorer substrate as compared to the
meso
-A
2
pm-containing one. Based on the respective substrate specificities of the chlamydial MurC, MurE, MurF and Ddl enzymes, a sequence
l
-Ala/
l
-Ser/Gly-γ-
d
-Glu-
meso
-A
2
pm-
d
-Ala-
d
-Ala is expected for the chlamydial pentapeptide stem, with Gly at position 1 being less likely.
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