Gang-Won Cheong

Learn More
Although a great deal is known biochemically about peroxiredoxins (Prxs), little is known about their real physiological function. We show here that two cytosolic yeast Prxs, cPrxI and II, which display diversity in structure and apparent molecular weights (MW), can act alternatively as peroxidases and molecular chaperones. The peroxidase function(More)
We found that Arabidopsis AtTDX, a heat-stable and plant-specific thioredoxin (Trx)-like protein, exhibits multiple functions, acting as a disulfide reductase, foldase chaperone, and holdase chaperone. The activity of AtTDX, which contains 3 tetratricopeptide repeat (TPR) domains and a Trx motif, depends on its oligomeric status. The disulfide reductase and(More)
The transit peptides of nuclear-encoded chloroplast proteins are necessary and sufficient for targeting and import of proteins into chloroplasts. However, the sequence information encoded by transit peptides is not fully understood. In this study, we investigated sequence motifs in the transit peptide of the small subunit of the Rubisco complex by examining(More)
The essential oil obtained from the leaves of Chamaecyparis obtusa was analyzed by GC and GC-MS. alpha-Terpinyl acetate, sabinene, isobornyl acetate and limonene were found to be the major components. The oil showed relatively strong antibacterial activities against Gram (+) bacteria and some fungi.
Sulfite reductase (SiR) performs dual functions, acting as a sulfur assimilation enzyme and as a chloroplast (cp-) nucleoid binding protein. In this study, we examined the in vivo effects of SiR deficiency on chloroplast development in Nicotiana benthamiana. Virus-induced gene silencing of NbSiR resulted in leaf yellowing and growth retardation phenotypes,(More)
Deblocking aminopeptidase (DAP) is an exoprotease that can release N-terminal amino acids from blocked peptides. Three DAP homologous (TkDAP1, TkDAP2, and TkDAP3) are annotated in the genome data base of Thermococcus kodakarensis KOD1. TkDAP2 and TkDAP3 were identified as proteins that are overexpressed in response to heat and oxidative stress by(More)
Escherichia coli HslVU is an ATP-dependent protease consisting of two heat shock proteins, the HslU ATPase and HslV peptidase. In the reconstituted enzyme, HslU stimulates the proteolytic activity of HslV by one to two orders of magnitude, while HslV increases the rate of ATP hydrolysis by HslU several-fold. Here we show that HslV alone can efficiently(More)
Peroxiredoxins (Prxs) act against hydrogen peroxide (H2O2), organic peroxides, and peroxynitrite. Thermococcus kodakaraensis KOD1, an anaerobic archaeon, contains many antioxidant proteins, including three Prxs (Tk0537, Tk0815, and Tk1055). Only Tk0537 has been found to be induced in response to heat, osmotic, and oxidative stress. Tk0537 was found to(More)
The small heat-shock protein (sHSP) from Methanococcus jannaschii (Mj HSP16.5) forms a homomeric complex of 24 subunits and has an overall structure of a multiwindowed hollow sphere with an external diameter of approximately 120 A and an internal diameter of approximately 65 A with six square "windows" of approximately 17 A across and eight triangular(More)
We studied the effects of melittin on various cell wall components and vesicles of various lipid compositions. To interact with the cytoplasmic membrane, melittin must traverse the cell wall, which is composed of oligosaccharides. Here, we found that melittin had a strong affinity for chitin, peptidoglycan, and lipopolysaccharide. We further examined the(More)