Endopeptidase Penicillin-Binding Proteins 4 and 7 Play Auxiliary Roles in Determining Uniform Morphology of<i>Escherichia coli</i>

Meberg, Bernadette M.; Paulson, Avery L.; Priyadarshini, Richa; Young, Kevin

doi:10.1128/jb.186.24.8326-8336.2004

Cited by 72 publications

(98 citation statements)

References 33 publications

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“…removal of inappropriate cross-links initiated by PBP5. In vivo the enzyme seems to behave as a DD-carboxypeptidase rather than a transpeptidase (46,47). In B. subtilis, it was shown that PBP4a is expressed during the late exponential phase but is dispensable for the synthesis of spore peptidoglycan (10,48).…”

Section: Discussionmentioning

confidence: 99%

Crystal Structure of the Actinomadura R39 DD-peptidase Reveals New Domains in Penicillin-binding Proteins

Sauvage

Herman

Pétrella³

et al. 2005

Journal of Biological Chemistry

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Actinomadura sp. R39 produces an exocellular DDpeptidase/penicillin-binding protein (PBP) whose primary structure is similar to that of Escherichia coli PBP4. It is characterized by a high ␤-lactam-binding activity (second order rate constant for the acylation of the active site serine by benzylpenicillin: k 2 /K ‫؍‬ 300 mM ؊1 s ؊1 ). The crystal structure of the DD-peptidase from Actinomadura R39 was solved at a resolution of 1.8 Å by single anomalous dispersion at the cobalt resonance wavelength. The structure is composed of three domains: a penicillin-binding domain similar to the penicillin-binding domain of E. coli PBP5 and two domains of unknown function. In most multimodular PBPs, additional domains are generally located at the C or N termini of the penicillin-binding domain. In R39, the other two domains are inserted in the penicillin-binding domain, between the SXXK and SXN motifs, in a manner similar to "Matryoshka dolls." One of these domains is composed of a five-stranded ␤-sheet with two helices on one side, and the other domain is a double threestranded ␤-sheet inserted in the previous domain. Additionally, the 2.4-Å structure of the acyl-enzyme complex of R39 with nitrocefin reveals the absence of active site conformational change upon binding the ␤-lactams.

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Section: Discussionmentioning

confidence: 99%

Crystal Structure of the Actinomadura R39 DD-peptidase Reveals New Domains in Penicillin-binding Proteins

Sauvage

Herman

Pétrella³

et al. 2005

Journal of Biological Chemistry

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“…Together with PBP5/DacA, PBP4/DacB is involved in maintaining normal cell morphology [105][106][107]. PBP5/DacA is found attached to the inner membrane [108].…”

Section: Low Molecular Mass Penicillin-binding Proteins (Lmm Pbps)mentioning

confidence: 99%

“…The GlcNAc-MurNAc peptide is reincorporated into the growing PG through high molecular mass (HMM) and LMM PBPs. respectively resulted in increased cell-shape defects as compared to the loss of dacA alone [106,118].…”

Section: Low Molecular Mass Penicillin-binding Proteins (Lmm Pbps)mentioning

confidence: 99%

Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance

Dhar

Kumari

Balasubramanian

et al. 2018

Journal of Medical Microbiology

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The bacterial cell-wall that forms a protective layer over the inner membrane is called the murein sacculus -a tightly crosslinked peptidoglycan mesh unique to bacteria. Cell-wall synthesis and recycling are critical cellular processes essential for cell growth, elongation and division. Both de novo synthesis and recycling involve an array of enzymes across all cellular compartments, namely the outer membrane, periplasm, inner membrane and cytoplasm. Due to the exclusivity of peptidoglycan in the bacterial cell-wall, these players are the target of choice for many antibacterial agents. Our current understanding of cell-wall biochemistry and biogenesis in Gram-negative organisms stems mostly from studies of Escherichia coli. An incomplete knowledge on these processes exists for the opportunistic Gram-negative pathogen, Pseudomonas aeruginosa. In this review, cell-wall synthesis and recycling in the various cellular compartments are compared and contrasted between E. coli and P. aeruginosa. Despite the fact that there is a remarkable similarity of these processes between the two bacterial species, crucial differences alter their resistance to b-lactams, fluoroquinolones and aminoglycosides. One of the common mediators underlying resistance is the amp system whose mechanism of action is closely associated with the cell-wall recycling pathway. The activation of amp genes results in expression of AmpC blactamase through its cognate regulator AmpR which further regulates multi-drug resistance. In addition, other cell-wall recycling enzymes also contribute to antibiotic resistance. This comprehensive summary of the information should spawn new ideas on how to effectively target cell-wall processes to combat the growing resistance to existing antibiotics.

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“…The loss of PBP4 fails to induce growth defects or detectable morphological alterations (49,165,170). The changes in PG structure accompanying PBP4 overproduction indicated that PBP4 acts in vivo as a DD-endopeptidase and a DD-carboxypeptidase but not as a DD-transpeptidase (130).…”

Section: Penicillin-binding Peptidasesmentioning

confidence: 99%

“…This finding indicates that PBP5 is acting in vivo on PG. Morphological defects accompanying the loss of PBP5 are visible by microscopic inspection (185), and shape changes with slight abnormalities at the poles are detectable by fluorescence-activated cell sorting (170). The overproduction of PBP5 is lethal, causing E. coli to grow as spherical cells before lysing (162,247).…”

Section: Penicillin-binding Peptidasesmentioning

confidence: 99%

Peptidoglycan Hydrolases of Escherichia coli

Heijenoort

2011

Microbiol Mol Biol Rev

190

233

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SUMMARY The review summarizes the abundant information on the 35 identified peptidoglycan (PG) hydrolases of Escherichia coli classified into 12 distinct families, including mainly glycosidases, peptidases, and amidases. An attempt is also made to critically assess their functions in PG maturation, turnover, elongation, septation, and recycling as well as in cell autolysis. There is at least one hydrolytic activity for each bond linking PG components, and most hydrolase genes were identified. Few hydrolases appear to be individually essential. The crystal structures and reaction mechanisms of certain hydrolases having defined functions were investigated. However, our knowledge of the biochemical properties of most hydrolases still remains fragmentary, and that of their cellular functions remains elusive. Owing to redundancy, PG hydrolases far outnumber the enzymes of PG biosynthesis. The presence of the two sets of enzymes acting on the PG bonds raises the question of their functional correlations. It is difficult to understand why E. coli keeps such a large set of PG hydrolases. The subtle differences in substrate specificities between the isoenzymes of each family certainly reflect a variety of as-yet-unidentified physiological functions. Their study will be a far more difficult challenge than that of the steps of the PG biosynthesis pathway.

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Endopeptidase Penicillin-Binding Proteins 4 and 7 Play Auxiliary Roles in Determining Uniform Morphology ofEscherichia coli

Cited by 72 publications

References 33 publications

Crystal Structure of the Actinomadura R39 DD-peptidase Reveals New Domains in Penicillin-binding Proteins

Crystal Structure of the Actinomadura R39 DD-peptidase Reveals New Domains in Penicillin-binding Proteins

Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance

Peptidoglycan Hydrolases of Escherichia coli

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