Lysine crotonylation has attracted widespread attention in recent years. However, little is known about bacterial crotonylation, particularly crotonyltransferase and decrotonylase, and its effects on ...antibiotic resistance. Our study demonstrates the ubiquitous presence of crotonylation in E. coli, which promotes bacterial resistance to polymyxin. We identify the crotonyltransferase YjgM and its regulatory pathways in E. coli with a focus on crotonylation. Further studies show that YjgM upregulates the crotonylation of the substrate protein PmrA, thereby boosting PmrA’s affinity for binding to the promoter of eptA, which, in turn, promotes EptA expression and confers polymyxin resistance in E. coli. Additionally, we discover that PmrA’s crucial crotonylation site and functional site is Lys 164. These significant discoveries highlight the role of crotonylation in bacterial drug resistance and offer a fresh perspective on creating antibacterial compounds.
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•YjgM functions as a crotonyltransferase in Escherichia coli•Crotonylation proteomics reveals differentially crotonylated proteins in PMB-R•YjgM promotes bacterial polymyxin resistance via the crotonylation of PmrA•Crotonylation promotes PmrA’s binding ability to the eptA promoter
Zhuang et al. find that YjgM is a crotonyltransferase in Escherichia coli. YjgM improves the binding affinity between the polymyxin-resistant protein PmrA and the eptA promoter by increasing the crotonoylation level of PmrA, thereby encouraging the expression of eptA, resulting in the development of polymyxin resistance in E. coli.
Antibiotic resistance is increasingly becoming a challenge to public health. The regulation of bacterial metabolism by post-translational modifications (PTMs) has been widely studied. However, the ...mechanism underlying the regulation of acetylation in bacterial resistance to antibiotics is still unknown. Here, we performed a quantitative analysis of the acetylated proteome of a wild-type (WT) Escherichia coli (E. coli) sensitive strain and ampicillin- (Re-Amp), kanamycin- (Re-Kan), and polymyxin B-resistant (Re-Pol) strains. Based on bioinformatics analysis combined with biochemical validations, we found a common regulatory mechanism between the different resistant strains. Our results showed that protein acetylation negatively regulates bacterial metabolism to regulate antibiotic resistance and positively regulates bacterial motility. Further analyses revealed that key enzymes in various metabolic pathways were differentially acetylated. In particular, pyruvate kinase (PykF), a glycolytic enzyme that regulates bacterial metabolism, and its acetylated form were highly expressed in the three resistant strains and were identified as reversibly acetylated by the deacetylase CobB and the acetyl-transferase PatZ (peptidyl-lysine
-acetyltransferase). Results showed that PykF also could be acetylated by nonenzymatic acetyl phosphatase (AcP)
. Furthermore, the deacetylation of Lys413 in PykF increased PykF enzymatic activity by changing the conformation of its ATP binding site, resulting in an increase in energy production which, in turn, increased the sensitivity of drug-resistant strains to antibiotics. This study provides novel insights for understanding bacterial resistance and lays the foundation for future research on the regulation of acetylation in antibiotic-resistant strains.
The misuse of antibiotics has resulted in the emergence of many antibiotic-resistant strains which seriously threaten human health. Protein post-translational modifications, especially acetylation, tightly control bacterial metabolism. However, the comprehensive mechanism underlying the regulation of acetylation in bacterial resistance remains unexplored. Here, acetylation was found to positively regulate bacterial motility and negatively regulate energy metabolism, which was common in all antibiotic-resistant strains. Moreover, the acetylation and deacetylation process of PykF was uncovered, and deacetylation of the Lys 413 in PykF was found to contribute to bacterial sensitivity to antibiotics. This study provides a new direction for research on the development of bacterial resistance through post-translational modifications and a theoretical basis for developing antibacterial drugs.
Infections caused by drug-resistant bacteria are a serious threat to public health worldwide, and the discovery of novel antibacterial compounds is urgently needed. Here, we screened an FDA-approved ...small-molecule library and found that crizotinib possesses good antimicrobial efficacy against Gram-positive bacteria. Crizotinib was found to increase the survival rate of mice infected with bacteria and decrease pulmonary inflammation activity in an animal model. Furthermore, it showed synergy with clindamycin and gentamicin. Importantly, the Gram-positive bacteria showed a low tendency to develop resistance to crizotinib. Mechanistically, quantitative proteomics and biochemical validation experiments indicated that crizotinib exerted its antibacterial effects by reducing ATP production and pyrimidine metabolism. A drug affinity responsive target stability study suggested crizotinib targets the CTP synthase PyrG, which subsequently disturbs pyrimidine metabolism and eventually reduces DNA synthesis. Subsequent molecular dynamics analysis showed that crizotinib binding occurs in close proximity to the ATP binding pocket of PyrG and causes loss of function of this CTP synthase. Crizotinib is a promising antimicrobial agent and provides a novel choice for the development of treatment for Gram-positive infections.
Infections caused by drug-resistant bacteria are a serious problem worldwide. Therefore, there is an urgent need to find novel drugs with good antibacterial activity against multidrug-resistant bacteria. In this study, we found that a repurposed drug, crizotinib, exhibits excellent antibacterial activity against drug-resistant bacteria both
and
via suppressing ATP production and pyrimidine metabolism. Crizotinib was found to disturb pyrimidine metabolism by targeting the CTP synthase PyrG, thus reducing DNA synthesis. This unique mechanism of action may explain the decreased development of resistance by Staphylococcus aureus to crizotinib. This study provides a potential option for the treatment of drug-resistant bacterial infections in the future.
Ciprofloxacin (CIP) is a prevalent environmental contaminant that poses a high risk of antibiotic resistance. High concentrations of antibiotics can lead to the development of resistant bacteria with ...high fitness costs, which often face a competitive disadvantage. However, it is unclear whether low-cost resistant bacteria formed by exposure to sub-MIC CIP in the environment can evolve competitive mechanisms against sensitive Escherichia coli (SEN) other than stronger resistance to CIP. Our study exposed E. coli to sub-MIC CIP levels, resulting in the development of CIP-resistant E. coli (CIPr). In antibiotic-free co-culture assays, CIPr outcompeted SEN. This indicates that CIPr is very likely to continue to develop and spread in antibiotic-free environments such as drinking water and affect human health. Further mechanism investigation revealed that bacterial membrane vesicles (BMVs) in CIPr, functioning as substance delivery couriers, mediated a cleavage effect on SEN. Proteomic analysis identified Entericidin B (EcnB) within CIPr-BMVs as a key factor in this competitive interaction. RT-qPCR analysis showed that the transcription of its negative regulator ompR/envZ was down-regulated. Moreover, EcnB plays a crucial role in the development of CIP resistance, and some resistance-related proteins and pathways have also been discovered. Metabolomics analysis highlighted the ability of CIPr-BMVs to acidify SEN, increasing the lytic efficiency of EcnB through cationization. Overall, our study reveals the importance of BMVs in mediating bacterial resistance and competition, suggesting that regulating BMVs production may be a new strategy for controlling the spread of drug-resistant bacteria.
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•CIP-resistant bacteria (CIPr) outcompete sensitive strains in the environment.•BMVs serve as crucial mediators of competition edge for resistant bacteria.•EcnB is critical for bacterial competition and CIP resistance.•CIPr -BMVs acidify SEN and enhance the cationicity of EcnB.•A novel mechanism reveals how CIPr thrives in the environment.
Single sideband (SSB) modulation based on a monolithic integrated optically injection-locked (MOIL) DFB laser is demonstrated experimentally. To our knowledge, this is the first time to realize SSB ...modulation utilizing a MOIL DFB laser. Tunable SSB signals with large lower-to-upper sideband power ratios are achieved by changing the bias currents of the MOIL DFB laser. The largest lower-to-upper sideband power ratio is measured to be 24.4 dB, which is very useful for improving the transmission performance of a radio-over-fiber link. Due to the generated SSB modulation, the fiber transmission response is flattened significantly and a signal of 25 GHz is transmitted through 85-km fiber without being affected by the fiber chromatic dispersion. 20 MSymbol/s 32-QAM signals with subcarriers of 21 GHz, 23 GHz, and 25 GHz are also transmitted by the proposed SSB modulation link, and both the error vector magnitude (EVM) and the bit error rate (BER) of the link are improved distinctly. The proposed method can effectively suppress the fiber chromatic dispersion.
A dual-frequency Doppler Lidar (DFDL) with high precision utilizing a monolithic integrated two-section DFB laser as the dual-frequency light source is proposed and experimentally demonstrated. The ...DFDL can be realized with smaller size using the monolithic integrated two-section DFB laser which is fabricated by the reconstruction-equivalent-chirp (REC) technique with high precision and low fabrication cost. The range of the measured speed is from 13.62 μm /s to 1.56 m/s, which covers 6 orders of magnitude. The largest relative error of the DFDL system is 3.16%. The DFDL system has an excellent resolution of 1.95 μm/s, which is suitable to detect micro speed changes.
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