Characterization of Chryseobacterium sp. extract using LC-QTOF-MS and molecular networking
Conference paper > Summary Text · 2023
Authors: Umut ŞAHAR, Didem AKSU, Mamadou Malick Diallo, Selin Sarıçayır, Pelin Sarıkaya, Güven ÖZDEMİR
International Proteomics Congress, 5thTurkish National Proteomics Congress, TuPa2023, Türkiye, Ankara, International, Verbal, Summary Text, 2023-2023, pp 20-20
Summary
<p>Aim: This study was aimed to characterize the chemical constituents of Chryseobacterium sp. by an untargeted strategy using LC-QTOF-MS combined with Molecular Networking (GNPS), identify potential target proteins (pharmacophore) for these molecules and monitor the antimicrobial activity.Method: The cells were removed from the media by centrifugation, supernatant was acidified and kept overnight at 4°C. Solution was extracted using chloroform: methanol. After extraction, supernatant and the dried extract were analyzed by LC-QTOF-MS. Untargeted MRM screening with gradient HPLC program on C18 column was performed. After file conversion for obtained spectra, molecular network was generated on GNPS platform. Pharmmapper was used to discover the probable inhibitors among these metabolites. The results were visualized on Cytoscape for complex network analyses. Antimicrobial activity of the extract against gram positive/negative bacteria was determined by disc diffusion method.Results: The untargeted LC-QTOF-MS/MS method was successfully applied for profiling of extracts. After molecular networking of LC-QTOF-MS/MS spectra, a total of 116 metabolites with distinctive fragment spectra were detected. Between these compounds, 28 amino acids/peptides and other small molecules e.g., fatty acids, alkaloids, were reported using GNPS platform. Bioinformatic results was revealed that some of dipeptides have high binding affinity (Normfit>0.90) values with several target bacterial proteins. The in vitro test results showed that the extract has antibacterial activity against all the five bacterial species and highest antibacterial activity was observed against B. cereus and B. subtilisConclusion: Bacterial metabolites are a major source of bioactive compounds. LC-QTOF-MS/MS and GNPS database combination was found to be a powerful method for rapid analysis of bioactive materials from Chryseobacterium sp. extracts without the help of reference standards. Using PharmMapper, possible antibacterial targets were identified, i.e., monomeric sarcosine oxidase (uniprot: P40859) from Bacillus sp. could be a target for N-butanoyl-DL-tryptophan with high fit score.</p>