• Journal of the Korean Magnetic Resonance Society
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• v.19 no.2
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• pp.74-82
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• 2015

Ryanodine receptor (RyR) is one of the two major $Ca^{2+}$ channels in membranes of intracellular $Ca^{2+}$ stores and is found in sarcoplasmic reticulum (SR), endoplasmic reticulum (ER). RyR1 is also the major calmodulin-binding protein of sarcoplasmic reticulum membranes. Residues 4064-4210 in the RyR1 polypeptide chain has similar primary sequence with calmodulin (CaM) and was designated as CaM-like domain (CaMLD). When expressed as a recombinant peptide, CaMLD showed several CaM-like properties in previous studies. Still, previous studies of CaMLD were focused on protein-protein interactions rather than its own properties. Here, we studied the expression of CaMLD and its sub-domains corresponding to each lobe of CaM in Escherichia coli. CaMLD could be obtained only as inclusion body, and it was refolded using urea solubilization followed by dialysis. Using spectroscopic approaches, such as NMR, circular dichroism, and gel filtration experiment, we found that the refolded CaMLD exists as nonspecific aggregate, even though it has alpha helical secondary structure. In comparison, the first half of CaMLD (R4061-4141) could be obtained as natively soluble protein with thioredoxin fusion. After the removal of the fusion tag, it exhibited folded and helical properties as shown by NMR and circular dichroism experiments. Its oligomeric status was different from CaMLD, existing as dimeric form in solution. However, the second half of the protein could not be obtained as soluble protein regardless of fusion tag. Based on these results, we believe that CaMLD, although similar to CaM in sequence, has quite different physicochemical properties and that the second half of the protein renders it the aggregative properties.

• Journal of the Korean Magnetic Resonance Society
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• v.18 no.1
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• pp.30-35
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• 2014

The transcription factor CP2 regulates various biological systems at diverse tissues and cells. However, none of the four CP2 isoforms has been solved in structure yet. In particular, two different regions of the CP2b isoform have been characterized to interact with the PIAS1 in nucleus to regulate the ${\alpha}$-globin gene expression. Among them, in this study, the region encompassing residues 251-309 of CP2b was prepared as a recombinant protein and its solution structure was characterized by NMR spectroscopy. The results indicated that the CP2b(251-309) fold belongs to typical IDRs (intrinsically disordered regions), likely to facilitate promiscuous interactions with various target proteins. Unfortunately, however, its interaction with the N-terminal domain of PIAS1 (residues 1-70), which has been identified as one of the CP2b-binding sites, was not observed in the NMR-based titration experiments. Therefore, it could be postulated that the 251-309 region of CP2b would not contact with the PIAS1(1-70), but alternatively interact with another CP2b-binding region that encompasses residues 400-651 of PIAS1.

• BMB Reports
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• v.34 no.3
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• pp.201-205
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• 2001

Thionins are a family of low molecular weight cysteine-rich antimicrobial peptides. We isolated a cDNA encoding thionin gene from a flower bud cDNA library of Chinese cabbage (CFT). The gene contains 611 by nucleotides with 60 bp, and 150 by untranslated regions at its N- and C-terminal, respectively. The deduced amino acid sequence encoded 133 amino acids containing precursor polypeptide. The protein reveals that the precursor has a tripartite structure: a putative signal sequence at the N-terminus, followed by a mature thionin peptide, and a C-terminal acidic domain, which facilitates transport of the mature thionin through membrane. Genomic Southern blot analysis suggests that the CFT gene may be present as a single or two copy gene in the Chinese cabbage genome. Northern blot analysis shows that the gene is specifically expressed in flowers, but not in leaves, stems, or roots. When we analyzed the antifungal activity of the recombinant CFT protein, which was expressed in E. coli using the truncated cDNA region corresponding to the mature protein part, it was not active on fungal growth inhibition.

• BMB Reports
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• v.45 no.6
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• pp.331-336
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• 2012

The retinoid-related orphan nuclear receptor gamma ($ROR{\gamma}$) plays critical roles in regulation of development, immunity and metabolism. As transcription factor usually forms a protein complex to function, thus capturing and dissecting of the $ROR{\gamma}$ protein complex will be helpful for exploring the mechanisms underlying those functions. After construction of the recombinant tandem affinity purification (TAP) plasmid, pMSCVpuro $ROR{\gamma}$-CTAP(SG), the nuclear localization of $ROR{\gamma}$-CTAP(SG) fusion protein was verified. Following isolation of $ROR{\gamma}$ protein complex by TAP strategy, seven candidate interacting proteins were identified. Finally, the heat shock protein 90 (HSP90) and receptor-interacting protein 140 (RIP140) were confirmed to interplay with $ROR{\gamma}$ by co-immunoprecipitation. Interference of HSP90 or/and RIP140 genes resulted in dramatically decreased expression of CYP2C8 gene, the $ROR{\gamma}$ target gene. Data from this study demonstrate that HSP90 and RIP140 proteins interact with $ROR{\gamma}$ protein in a complex format and function as co-activators in the $ROR{\gamma}$-mediated regulatory processes of HepG2 cells.

• Toxicological Research
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• v.26 no.3
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• pp.171-175
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• 2010

The human genome contains approximately 13 orphan cytochrome P450 (P450, CYP) genes, of which the apparent function or substrate has not been identified. However, they seem to possess their own biological relevance in some tissues or developmental stages. Here, we characterized the heterologously expressed CYP2W1, an orphan P450 enzyme. The recombinant CYP2W1 protein containing a $6{\times}$(His)-tag at Nterminus has been expressed in Escherichia coli and purified. Expression level of CYP2W1 holoenzyme was around 500 nmol P450 holoenzyme per liter culture medium. The reduced CO difference spectrum of CYP2W1 showed a maximum absorption at 449 nm. CYP2W1 indicated the significant induction to bioactivate Trp-P-1, MeIQ, and IQ in E. coli DJ701 tester strain. However, the bioactivation of B[$\alpha$]P, and NNK by CYP2W1 was relatively low. The model structure of CYP2W1 suggested the characteristic P450 folds with the lengths and orientations of the individual secondary elements. The F-G loop is situated on the distal side of heme to accommodate the flexibility of active site of CYP2W1. These studies can provide useful information for the finding of its biological roles and structure-function relationships of an orphan CYP2W1 enzyme.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1232-1238
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• 2004

To investigate the production and characteristics of thermostable levan sucrase from Rahnella aquatilis ATCC 33071, the levan sucrase gene from R. aquatilis was cloned and expressed in Escherichia coli without induction system. Expression of levansucrase gene in E. coli had no notable or detrimental effect on the growth of host strain, and the recombinant levan sucrase exhibited levan synthesis activity. Levansucrase was secreted to the periplasm in E. coli, and addition of $0.5\%$ glycine yielded further secretion of levansucrase to the growth medium and resulted in an increase of total levansucrase activity. Furthermore, the cellular levansucrase was evaluated for the production of levan by using toluene­permeabilized whole-cells. The levansucrase was thermostable at $37^{\circ}C$. The molecular size oflevan was $1{\times}\;10^{6}$ Da, as determined by HPLC, and the degree of polymerization of levan varied with incubation temperatures: Low incubation temperature was preferable for the production of high-molecular size levan. The present study demonstrated that the mass production of levan and levan oligosaccharides can be achieved by glycine supplementation to the growth medium or by toluene­permeabilized whole-cells.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1343-1349
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• 2004

A native strain of Pasteurella multocida was isolated from pigs suffering from severe atrophic rhinitis at domestic farms in Gyeonggi Province, Korea, and was identified as capsular serogroup 'D' and somatic serotype '4' by disc diffusion decapsulation and gel diffusion precipitation tests, respectively. The P. multocida (D:4) induced atrophic rhinitis in healthy pigs by the secondary infection. The gene for outer membrane protein H (ompH) of P. multocida (D:4) was cloned in Escherichia coli DH5$\alpha$ by PCR. The open reading frame of the ompH was composed of 1,023 bp, possibly encoding a protein with 341 amino acid residues containing a signal peptide of 20 amino acids at N-terminus, and the gene product with molecular mass of ca. 38 kDa was identified by SDS-PAGE. Hydropathy profiles indicated that there are two variable domains in the OmpH. To express the ompH in E. coli, the gene was manipulated in various ways. Expression of the truncated as well as full-length forms of the recombinant OmpH was fatal to the host E. coli BL21 (DE3). However, the truncated OmpH fused with GST was consecutively expressed in E. coli DH5$\alpha$. A large quantity of the fused polypeptide was purified through GST-affinity chromatography.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1310-1316
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• 2005

To evaluate the toxicological properties of human cytochrome P450 2E1 (CYP2E1) induced by ethanol and possible protective effects of various green tea catechins on alcohol-induced toxicity, transfected HepG2 cells that stably and constitutively express human CYP2E1 were established using the recombinant retroviral expression vector. Exposure of the CYP2E1-expressing HepG2 cells to high concentration of ethanol (200 mM) for 5 days resulted in a more than $50\%$ increase of cytotoxicity, assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction, lactate dehydrogenase (LDH) release, and reactive oxygen species (ROS) production, and loss of normal morphology, in comparison with HepG2 cells containing control vector. Treatment of the cells with various catechins increased cell viability by more than 2-fold. (-)-Epicatechin gallate and(-)-catechin gallate at the lowest concentration ($5\;{\mu}M$) attenuated cell death induced CYP2E1 by $60-65\%$. Therefore, the results showed that the catechins, including epimerized catechins, have strong protective effects against alcohol-induced CYP2E1 toxicity, and it is correlated with antioxidant effect.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.206-211
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• 2004

Levansucrase gene(lscA) from Pseudomonas aurantiaca was subcloned downstream of GAL1 promoter in pYES 2.0 and pYInu-AT [GAL10 promoter ＋ exoinulinase signal sequence of Kluyveromyces marxianus], resulting pYES-lscA and p YInu-lscA, respectively. The two expression plasmids were introduced into an invertase-deficient strain, Sacchromayces cerevisiae SEY2102, and transformants with high activity of levansucrase were selected. When each yeast transform ants was cultivated in medium containing galactose, the extracellular and intracellular activities of levansucrase reached about 8.62 U/ml with the strain harboring pYES-lscA and 5.43 U/ml with the strain harboring pYInu-lscA. The levansucrase activity of 80% was detected in the periplasmic space and cytoplasm. The levansucrase activity in the medium of SEY2102/pYInu-lscA was 0.87 U/ml whereas that of SEY2102/pYES-lscA was 0.47 U/ml, which implying the exoinulinase signal sequence didn't enhance the secretion efficiency of levansucrase. Furthermore, the recombinant levansucrase expressed in yeast seems to be produced as a hyper-glycosylated form.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1267-1272
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• 2005

The effects of coexpression of GroEL/ES and DnaK/DnaJ/GrpE chaperones on the productivity of the soluble form of human granulocyte colony stimulating factor (hG-CSF) in E. coli were examined. Recombinant hG-CSF protein was coexpressed with DnaK/DnaJ/GrpE or GroEL/ES chaperones under the control of the araB or Pzt-1 promoter, respectively. The optimal concentration of L-arabinose for the expression of DnaK/DnaJ/GrpE was found to be 1 mg/ml. When L-arabinose was added at $OD_{600}$=0.2 (early-exponential phase), soluble hG-CSF production was greatly increased. In addition, it was observed that the DnaK/DnaJ/GrpE and GroEL/ES chaperones had no synergistic effects on preventing aggregation of hG-CSF protein. Consequently, by coexpression of the DnaK/DnaJ/GrpE chaperone, the signal intensity of the hG-CSF protein band in the soluble fraction of cell lysate was increased from $3.5\%\;to\;13.9\%$, and Western blot analysis also revealed about a 4-5-fold increase of production of soluble hG-CSF over the non-induction case of DnaK/DnaJ/GrpE.