Diversity in E. coli (p)ppGpp Levels and Its Consequences

Spira, Beny; Ospino, Katia

doi:10.3389/fmicb.2020.01759

Cited by 27 publications

(22 citation statements)

References 91 publications

(141 reference statements)

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“…1 ), which triggered a greater decrease in bacterial ppGpp level than IDR-1018. ppGpp as a master regulator of almost all aspects of bacterial physiology including biofilm formation (Hobbs and Boraston 2019 ), supports the bacteria survival by either directly or indirectly stimulating the expression of genes involved in stress protection (Spira and Ospino 2020 ). Reduced ppGpp concentration weakened the tolerance capability of bacteria against stress conditions, thus leading to a formation inhibition of biofilm.…”

Section: Discussionmentioning

confidence: 99%

Design of a novel antimicrobial peptide 1018M targeted ppGpp to inhibit MRSA biofilm formation

et al. 2021

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Methicillin-resistant staphylococcus aureus (MRSA) and its biofilm infection were considered as one of the main international health issues. There are still many challenges for treatment using traditional antibiotics. In this study, a mutant peptide of innate defense regulator (IDR-)1018 named 1018M was designed based on molecular docking and amino acid substitution technology. The antibacterial/biofilm activity and mechanisms against MRSA of 1018M were investigated for the first time. The minimum inhibitory concentration (MIC) of 1018M was reduced 1 time (MIC = 2 μg/mL) compared to IDR-1018. After treatment with 32 μg/mL 1018M for 24 h, the percentage of biofilm decreased by 78.9%, which was more effective than the parental peptide. The results of mechanisms exploration showed that 1018M was more potent than IDR-1018 at destructing bacterial cell wall, permeating cell membrane (20.4%–50.1% vs 1.45%–10.6%) and binding to stringent response signaling molecule ppGpp (increased 27.9%). Additionally, the peptides could also exert their activity by disrupting genomic DNA, regulating the expression of ppGpp metabolism and biofilm forming related genes (RSH, relP, relQ, rsbU, sigB, spA, codY, agrA and icaD). Moreover, the higher temperature, pH and pepsase stabilities provide 1018M better processing, storage and internal environmental tolerance. These data indicated that 1018M may be a potential candidate peptide for the treatment of MRSA and its biofilm infections.

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Section: Discussionmentioning

confidence: 99%

Design of a novel antimicrobial peptide 1018M targeted ppGpp to inhibit MRSA biofilm formation

et al. 2021

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“…Consistent with these, purine nucleotides such as (p)ppGpp function as universal alarmones for transcriptionally activating the stringent response and other bacterial stress responses as evolutionally conserved strategies for surviving nutrient limitation and other environmental stressors ( 66 , 67 ). Intracellular accumulation of (p)ppGpp and related purine alarmones can induce antibiotic tolerance by promoting growth arrest ( 68 ) and entry to antibiotic persister states ( 69 ). Recent studies demonstrate that in additional to these transcriptionally mediated programs, (p)ppGpp can also inhibit nucleotide metabolism directly by binding several enzymes involved in purine biosynthesis, including PurF and Gsk ( 70 , 71 ).…”

Section: Nucleotide Metabolism In Antibiotic Treatment Failurementioning

confidence: 99%

Digital Insights Into Nucleotide Metabolism and Antibiotic Treatment Failure

Lopatkin

Yang

2021

Front. Digit. Health

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Nucleotide metabolism plays a central role in bacterial physiology, producing the nucleic acids necessary for DNA replication and RNA transcription. Recent studies demonstrate that nucleotide metabolism also proactively contributes to antibiotic-induced lethality in bacterial pathogens and that disruptions to nucleotide metabolism contributes to antibiotic treatment failure in the clinic. As antimicrobial resistance continues to grow unchecked, new approaches are needed to study the molecular mechanisms responsible for antibiotic efficacy. Here we review emerging technologies poised to transform understanding into why antibiotics may fail in the clinic. We discuss how these technologies led to the discovery that nucleotide metabolism regulates antibiotic drug responses and why these are relevant to human infections. We highlight opportunities for how studies into nucleotide metabolism may enhance understanding of antibiotic failure mechanisms.

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“…The evidence is largely tantalizing. On the lines that there is reciprocal inter-domain regulation between HD and the SYN domains of the NTD of long RSHs (Tamman et al ., 2019, Takada et al ., 2021), it is interesting to note that mutations in the inactive HD domain of E. coli RelA reducing the SYN activity (Montero et al ., 2014, Spira & Ospino, 2020) may reflect the relic of this regulation. Although the catalytic amino acid residues of the HD domain are clearly absent in the monofunctional RelA, there is evolutionary conservation of the HD sequence all along this region between bifunctional RSHs and RelA, suggesting a possible important function.…”

Section: Discussionmentioning

confidence: 99%

Fusion of the N-terminal 119 amino acids with the RelA-CTD renders its growth inhibitory effects ppGpp-dependent

Tailor

Sagar

Dave

et al. 2021

Preprint

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The guanosine nucleotide derivatives ppGpp and pppGpp are central to the remarkable capacity of bacteria to adapt to fluctuating environment and metabolic perturbations. These alarmones are synthesized by two proteins, RelA and SpoT in E. coli and the activities of each of the two enzymes are highly regulated for homeostatic control of (p)ppGpp levels in the cell. Although the domain structure and function of RelA are well defined, the findings of this study unfold the regulatory aspect of RelA that is possibly relevant in vivo. We uncover here the importance of the N-terminal 1-119 amino acids of the enzymatically compromised (p)ppGpp hydrolytic domain (HD) of monofunctional RelA for the (p)ppGpp mediated regulation of RelA-CTD function. We find that even moderate level expression of RelA appreciably reduces growth when the basal levels of (p)ppGpp in the cells are higher than in the wild type, an effect independent of its ability to synthesize (p)ppGpp. This is evidenced by the growth inhibitory effects of oversynthesis of the RelA-CTD in the relA+ strain but not in relA null mutant, suggesting the requirement of the functional RelA protein for basal level synthesis of (p)ppGpp, accordingly corroborated by the restoration of the growth inhibitory effects of the RelA-CTD expression in the relA1 spoT202 mutant. The N-terminal 119 amino acids of RelA fused in-frame with the RelA-CTD, both from 406-744 amino acids (including TGS) and from 454-744 amino acids (sans TGS) caused growth inhibition only in spoT1 and spoT202 relA1 mutants, uncovering the hitherto unrealized (p)ppGpp-dependent regulation of RelA-CTD function. An incremental rise in the (p)ppGpp levels is proposed to progressively modulate the interaction of RelA-CTD with the ribosomes, with possible implications in the feedback regulation of the N-terminal (p)ppGpp synthesis function, a proposal that best explains the nonlinear relationship between (p)ppGpp synthesis and increased ratio of RelA:ribosomes, both in vitro as well as in vivo.

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Diversity in E. coli (p)ppGpp Levels and Its Consequences

Cited by 27 publications

References 91 publications

Design of a novel antimicrobial peptide 1018M targeted ppGpp to inhibit MRSA biofilm formation

Design of a novel antimicrobial peptide 1018M targeted ppGpp to inhibit MRSA biofilm formation

Digital Insights Into Nucleotide Metabolism and Antibiotic Treatment Failure

Fusion of the N-terminal 119 amino acids with the RelA-CTD renders its growth inhibitory effects ppGpp-dependent

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