Biomedical subjects

Sung-Ho Yun

Publications and source records attributed to Sung-Ho Yun.

6 recordsLinked to original sources

PubMed2006

Proteome analysis of cellular response of Pseudomonas putida KT2440 to tetracycline stress.

Tetracycline-induced proteome of Pseudomonas putida KT2440 was analyzed by 2-D gel electrophoresis and matrix-assisted laser desorption ionization-time of flight/mass spectrum (NALDI-TOF/MS) in order to understand cellular response to tetracycline. Of the proteins upregulated in a culture medium containing subinhibitory concentration of tetracycline (50 mug/mL), we identified 38 proteins from cytosol and precipitated fractions by peptide mass fingerprinting and mass spectrum/mass spectrum analysis. Various amino acids ABC transporters, a ribose ABC transporter, and a sulfate ABC transporter were found to be upregulated. Protein synthesis-related proteins, stress proteins, energy metabolic enzymes, and unknown proteins were also strongly induced. Of the identified upregulated proteins, several proteins (isocitrate lyase, branched-chain amino acid ABC transporter, superoxide dismutase, etc.) were also upregulated under phenol-induced stress condition. These results demonstrate that tetracycline at a high concentration induced comprehensive stress in P. putida KT2440 and the global induction of proteins related to bacteria survival. Proteome analysis was found to be a useful tool for the elucidation of antibiotic-induced proteins in the present study.

Bacterial Proteins↗

PubMed2006

Human plasma proteome analysis by reversed sequence database search and molecular weight correlation based on a bacterial proteome analysis.

In shotgun proteomics, proteins can be fractionated by 1-D gel electrophoresis and digested into peptides, followed by liquid chromatography to separate the peptide mixture. Mass spectrometry generates hundreds of thousands of tandem mass spectra from these fractions, and proteins are identified by database searching. However, the search scores are usually not sufficient to distinguish the correct peptides. In this study, we propose a confident protein identification method for high-throughput analysis of human proteome. To build a filtering protocol in database search, we chose Pseudomonas putida KT2440 as a reference because this bacterial proteome contains fewer modifications and is simpler than the human proteome. First, the P. putida KT2440 proteome was filtered by reversed sequence database search and correlated by the molecular weight in 1-D-gel band positions. The characterization protocol was then applied to determine the criteria for clustering of the human plasma proteome into three different groups. This protein filtering method, based on bacterial proteome data analysis, represents a rapid way to generate higher confidence protein list of the human proteome, which includes some of heavily modified and cleaved proteins.

Blood Proteins↗

PubMed2006

Analysis of aromatic catabolic pathways in Pseudomonas putida KT 2440 using a combined proteomic approach: 2-DE/MS and cleavable isotope-coded affinity tag analysis.

Proteomic analysis of Pseudomonas putida KT2440 cultured in monocyclic aromatic compounds was performed using 2-DE/MS and cleavable isotope-coded affinity tag (ICAT) to determine whether proteins involved in aromatic compound degradation pathways were altered as predicted by genomic analysis (Jiménez et al., Environ Microbiol. 2002, 4, 824-841). Eighty unique proteins were identified by 2-DE/MS or MS/MS analysis from P. putida KT2440 cultured in the presence of six different organic compounds. Benzoate dioxygenase (BenA, BenD) and catechol 1,2-dioxygenase (CatA) were induced by benzoate. Protocatechuate 3,4-dixoygenase (PcaGH) was induced by p-hydroxybenzoate and vanilline. beta-Ketoadipyl CoA thiolase (PcaF) and 3-oxoadipate enol-lactone hydrolase (PcaD) were induced by benzoate, p-hydroxybenzoate and vanilline, suggesting that benzoate, p-hydroxybenzoate and vanilline were degraded by different dioxygenases and then converged in the same beta-ketoadipate degradation pathway. An additional 110 proteins, including 19 proteins from 2-DE analysis, were identified by cleavable ICAT analysis for benzoate-induced proteomes, which complemented the 2-DE results. Phenylethylamine exposure induced beta-ketoacyl CoA thiolase (PhaD) and ring-opening enzyme (PhaL), both enzymes of the phenylacetate (pha) biodegradation pathway. Phenylalanine induced 4-hydroxyphenyl-pyruvate dioxygenase (Hpd) and homogentisate 1,2-dioxygenase (HmgA), key enzymes in the homogentisate degradation pathway. Alkyl hydroperoxide reductase (AphC) was induced under all aromatic compounds conditions. These results suggest that proteome analysis complements and supports predictive information obtained by genomic sequence analysis.

Affinity Labels↗

PubMed2006

Characterization of beta-ketoadipate pathway from multi-drug resistance bacterium, Acinetobacter baumannii DU202 by proteomic approach.

In this study, the biodegradative activities of monocyclic aromatic compounds were determined from the multi-drug resistant (MDR) Acinetobacter baumannii, which were studied in the form of clinical isolates from a hospital in Korea. These bacteria were capable of biodegrading monocyclic aromatic compounds, such as benzoate and p-hydroxybenzoate. In order to determine which pathways are available for biodegradation in these stains, we conducted proteome analyses of benzoate and p-hydroxybenzoate-cultured A. baumannii DU202, using 2-DE/MS analysis. As genome DB of A. baumannii was not yet available, MS/MS analysis or de novo sequencing methods were employed in the identification of induced proteins. Benzoate branch enzymes [catechol 1,2-dioxygenase (CatA) and benzoate dioxygenase alpha subunit (BenA)] of the beta-ketoadipate pathway were identified under benzoate culture condition and p-hydroxybenzoate branch enzymes [protocatechuate 3,4-dioxygenase alpha subunit (PcaG) and 3-carboxy-cis,cis-muconate cycloisomerase (PcaB)] of the beta-ketoadipate pathway were identified under p-hydroxybenzoate culture condition, respectively, thereby suggesting that strain DU202 utilized the beta-ketoadipate pathway for the biodegradation of monocyclic aromatic compounds. The sequence analysis of two purified dioxygenases (CatA and PcaGH) indicated that CatA is closely associated with the CatA of Acinetobacter radiresistance, but PcaGH is only moderately associated with the PcaGH of Acinetobacter sp. ADP1. Interestingly, the fused form of PcaD and PcaC, carboxymuconolactone decarboxylase (PcaCD), was detected on benzoate-cultured A. baumannii DU202. These results indicate that A. baumannii DU202 exploits a different beta-ketoadipate pathway from other Acinetobacter species.

Acinetobacter baumannii↗

PubMed2004

Proteome analysis of Pseudomonas sp. K82 biodegradation pathways.

Pseudomonas sp. K82 is a soil bacterium that can degrade and use monocyclic aromatic compounds including aniline, 3-methylaniline, 4-methylaniline, benzoate and p-hydroxybenzoate as its sole carbon and energy sources. In order to understand the impact of these aromatic compounds on metabolic pathways in Pseudomonas sp. K82, proteomes obtained from cultures exposed to different substrates were displayed by two-dimensional gel electrophoresis and were compared to search for differentially induced metabolic enzymes. Column separations of active fractions were performed to identify major biodegradation enzymes. More than thirty proteins involved in biodegradation and other types of metabolism were identified by electrospray ionization-quadrupole time of flight mass spectrometry. The proteome analysis suggested that Pseudomonas sp. K82 has three main metabolic pathways to degrade these aromatic compounds and induces specific metabolic pathways for each compound. The catechol 2,3-dioxygenase (CD2,3) pathway was the major pathway and the catechol 1,2-dioxygenase (beta-ketoadipate) pathway was the secondary pathway induced by aniline (aniline analogues) exposure. On the other hand, the catechol 1,2-dioxygenase pathway was the major pathway induced by benzoate exposure. For the degradation of p-hydroxybenzoate, the protocatechuate 4,5-dioxygenase pathway was the major degradation pathway induced. The nuclear magnetic resonance analysis of substrates demonstrated that Pseudomonas sp. K82 metabolizes some aromatic compounds more rapidly than others (benzoate > p-hydroxybenzoate > aniline) and that when combined, p-hydroxybenzoate metabolism is repressed by the presence of benzoate or aniline. These results suggest that proteome analysis can be useful in the high throughput study of bacterial metabolic pathways, including that of biodegradation, and that inter-relationships exist with respect to the metabolic pathways of aromatic compounds in Pseudomonas sp. K82.

Aniline Compounds↗

PubMed2004

Characterization of protocatechuate 4,5-dioxygenase induced from p-hydroxybenzoate-cultured Pseudomonas sp. K82.

Pseudomonas sp. K82 has been reported to be an aniline-assimilating soil bacterium. However, this strain can use not only aniline as a sole carbon and energy source, but can also utilize benzoate, p-hydroxybenzoate, and aniline analogues. The strain accomplishes this metabolic diversity by using different aerobic pathways. Pseudomonas sp. K82, when cultured in p-hydroxybenzoate, showed extradiol cleavage activity of protocatechuate. In accordance with those findings, our study attempted the purification of protocatechuate 4,5-dioxygenase (PCD 4,5). However the purified PCD 4,5 was found to be very unstable during purification. After Q-sepharose chromatography was performed, the crude enzyme activity was augmented by a factor of approximately 4.7. From the Q-sepharose fraction which exhibited PCD 4,5 activity, two subunits of PCD4,5 (alpha subunit and beta subunit) were identified using the N-terminal amino acid sequences of 15 amino acid residues. These subunits were found to have more than 90% sequence homology with PmdA and PmdB of Comamonas testosteroni. The molecular weight of the native enzyme was estimated to be approximately 54 kDa, suggesting that PCD4,5 exists as a heterodimer (alpha1beta1). PCD 4,5 exhibits stringent substrate specificity for protocatechuate and its optimal activity occurs at pH 9 and 15 degrees C. PCR amplification of these two subunits of PCD4,5 revealed that the alpha subunit and beta subunit occurred in tandem. Our results suggest that Pseudomonas sp. K82 induced PCD 4,5 for the purpose of p-hydroxybenzoate degradation.

Amino Acid Sequence↗