Min-A Kwon
Kyung Hee University
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Featured researches published by Min-A Kwon.
Applied Microbiology and Biotechnology | 2011
Eun Young Yu; Min-A Kwon; Miae Lee; Joon Young Oh; Ji-Eun Choi; Ji Young Lee; Bongkeun Song; Dae-Hyun Hahm; Jae Kwang Song
Functional screening for lipolytic enzymes at low temperatures resulted in the isolation of the novel cold-active esterases, EstM-N1 and EstM-N2, from a metagenomic DNA library of arctic soil samples. EstM-N1 and EstM-N2 were 395 and 407 amino acids in length, respectively, and showed the highest similarity to class C β-lactamases. However, they shared a relatively low level of sequence similarity (30%) with each other. Phylogenetic analysis of bacterial lipolytic enzymes confirmed that EstM-N1 and EstM-N2 belonged to family VIII of bacterial esterases/lipases. The (His)6-tagged esterases were purified to about 99% homogeneity from the soluble fraction of recombinant Escherichia coli cultures. The purified EstM-N1 and EstM-N2 retained more than 50% of maximal activity in the temperature range of 0–35°C, with optimal temperatures of 20°C and 30°C, respectively. Both enzymes preferred the short acyl chains of p-nitrophenyl esters and exhibited very narrow substrate specificity, indicating that they are typical esterases. The β-lactamase activity of EstM-N1 and EstM-N2 was also detected and reached about 31% and 13% of the positive control enzyme, Bacillus cereus β-lactamase, respectively. These first cold-active esterases belonging to family VIII are expected to be useful for potential biotechnological applications as interesting biocatalysts.
Protein Expression and Purification | 2009
Min-A Kwon; Hyun Suk Kim; Taek Ho Yang; Bong Keun Song; Jae Kwang Song
High-level extracellular production of Fusarium solani cutinase was achieved using a Pichia pastoris expression system. The cutinase-encoding gene was cloned into pPICZalphaA with the Saccharomyces cerevisiae alpha-factor signal sequence and methanol-inducible alcohol oxidase promoter by two different ways. The additional sequences of the c-myc epitope and (His)6-tag of the vector were fused to the C-terminus of cutinase, while the other expression vector was constructed without any additional sequence. P. pastoris expressing the non-tagged cutinase exhibited about two- and threefold higher values of protein amount and cutinase activity in the culture supernatant, respectively. After simple purification by diafiltration process, both cutinases were much the same in the specific activity and the biochemical properties such as the substrate specificity and the effects of temperature and pH. In conclusion, the high-level secretion of F. solani cutinase in P. pastoris was demonstrated for the first time and would be a promising alternative to many expression systems previously used for the large-scale production of F. solani cutinase in Saccharomyces cerevisiae as well as Escherichia coli.
Journal of Biotechnology | 2010
Taek Ho Yang; Min-A Kwon; Jae Kwang Song; Jae Gu Pan
Functional expression of the industrially important Pseudomonas and Burkholderia lipases, such as those from P. aeruginosa, B. cepacia and P. fluorescens, was achieved on the cell surface of Escherichia coli using the C-terminal translocator moiety (EstATu) of autotransporter protein (EstA) from P. putida. In particular, lipases which required a lipase-specific foldase (Lif) for their proper folding were for the first time displayed in the active form by coexpression of the Lif protein.
Biotechnology Letters | 2011
Min-A Kwon; Hyun Suk Kim; Dae-Hyun Hahm; Jae Kwang Song
A new zymography method for lipases and esterases was developed on the basis of the esterification reaction between fatty acids and alcohols. The enzymes were separated by SDS-PAGE and native PAGE. The gel was washed and then incubated in an aqueous solution containing fatty acids (oleic acid 18:1 or caprylic acid 8:0) and dodecanol. Synthesis was visualized by in situ precipitation of water-insoluble and non-diffusible fatty acid esters, such as dodecyl oleate and dodecyl octanoate. The synthesis activity-based zymography was confirmed with different enzyme samples, including commercial lipase preparations, purified recombinant lipase and cutinase, and crude culture supernatants of lipolytic enzyme-producing soil bacteria.
Journal of Microbiology and Biotechnology | 2009
Min-A Kwon; Hyun Suk Kim; Joon Young Oh; Bong Keun Song; Jae Kwang Song
Extremophiles | 2013
Ji-Eun Choi; Min-A Kwon; Hye Young Na; Dae-Hyun Hahm; Jae Kwang Song
Applied Biochemistry and Biotechnology | 2015
Taek Ho Yang; Min-A Kwon; Ji Young Lee; Ji-Eun Choi; Joon Young Oh; Jae Kwang Song
한국생물공학회 학술대회 | 2011
Taek Ho Yang; Min-A Kwon; Ji-Eun Choi; Jae Kwang Song
한국미생물학회 학술대회논문집 | 2009
Joon Young Oh; Min-A Kwon; Hyun Suk Kim; Gyeong Tae Eom; Eun Young Yu; Bong Keun Song; Jae Kwang Song
한국미생물학회 학술대회논문집 | 2009
Min-A Kwon; Eun Young Yu; Hyun Suk Kim; Joon Young Oh; Miae Lee; Bong Keun Song; Jae Kwang Song