• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1192-1195
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• 2010

To investigate the influence of the N- or C-terminal regions of pleurocidin (Ple) peptide on antifungal activity, four analogs partially truncated in the N- or C-terminal regions were designed and synthesized. Circular dichroism (CD) spectroscopy demonstrated that all the analogs maintained an alpha-helical structure. The antifungal susceptibility testing also showed that the analogs exhibited antifungal activities against human fungal pathogens, without hemolytic effects against human erythrocytes. The result further indicated that the analogs had discrepant antifungal activities [Ple>Ple (1-22)>Ple (4-25)>Ple (1- 19)>Ple (7-25)] and that N-terminal deletion affected the activities much more than C-terminal deletion. Hydrophobicity [Ple>Ple (1-22)>Ple (4-25)>Ple (1-19)> Ple (7-25)] was thought to have been one of the consistent factors that influenced these activity patterns, rather than the other primary factors like the helicity [Ple>Ple (4-25) >Ple (1-22)>Ple (1-19)>Ple (7-25)] or the net charge [Ple=Ple (4-25)=Ple (7-25)>Ple (1-22)=Ple (1-19)] of the peptides. In conclusion, the hydrophobic amino acids in the N-terminal region of Ple is more crucial for antifungal activity than those in the C-terminal region.

• Journal of Genetic Medicine
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• v.8 no.1
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• pp.62-66
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• 2011

Deletions of 14q including band 14q32.33 are uncommon. Patients with terminal deletions of chromosome 14 usually share a number of clinical features. By molecular techniques (array comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH), we identified a young girl with 0.3 Mb terminal 14q32.33 deletion. Review of the nine cases with pure terminal 14q32.3 deletions described to date documented that our observation is the smallest terminal 14q deletion ever reported. The phenotype of our patient is much less severe than the phenotypes of the patients reported previously. We report our experience in examining the clinical, behavioral, and cognitive findings in a 5-year-old girl studied with chromosomal microarray hybridization and reviewed previously reported patients with 14q32 deletions.

• BMB Reports
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• v.29 no.5
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• pp.411-416
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• 1996

In order to study the role of the protein shell in both iron uptake and iron core formation of ferritin, we constructed a deletion mutant of the ferritin gene and expressed the mutant gene in Escherichia coli, This mutant was obtained by introducing an amber mutation at position Pro-157 and a deletion of the 19 amino acid residues at the carboxy-terminus of the recombinant tadpole H-chain ferritin. The deleted amino acids correspond to E-helix forming the hydrophobic channel in the protein. E. coli harboring the plasmid pTHP157, which contains the deleted gene, was grown at $23^{\circ}C$ in the presence of 0.1 mM IPTG, and the induced protein appeared to be partly soluble. Nondenaturing polyacrylamide gel electrophoresis showed that the expressed mutant H-chains coassemble into holoprotein, suggesting that E-helix is not necessary for assembly of the subunits as reported for human H-chain ferritin. Its ability in iron core formation was proven in an Fe staining gel, the result disagreeing with the observation that the hydrophobic channel is necessary for iron core formation in human H-chain ferritin.

• Microbiology and Biotechnology Letters
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• v.51 no.3
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• pp.243-249
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• 2023

We recently found that the insect-derived antimicrobial peptide CopA3 (LLCIALRKK) directly binds to and inhibits the proteolytic activation of caspases, which play essential roles in apoptotic processes. However, the mechanism of CopA3 binding to caspases remained unknown. Here, using recombinant GST-caspase-3 and -6 proteins, we investigated the mechanism by which CopA3 binds to caspases. We showed that replacement of cysteine in CopA3 with alanine caused a marked loss in its binding activity towards caspase-3 and -6. Exposure to DTT, a reducing agent, also diminished their interaction, suggesting that this cysteine plays an essential role in caspase binding. Experiments using deletion mutants of CopA3 showed that the last N-terminal leucine residue of CopA3 peptide is required for binding of CopA3 to caspases, and that C-terminal lysine and arginine residues also contribute to their interaction. These conclusions are supported by binding experiments employing direct addition of CopA3 deletion mutants to human colonocyte (HT29) extracts containing endogenous caspase-3 and -6 proteins. In summary, binding of CopA3 to caspases is dependent on a cysteine in the intermediate region of the CopA3 peptide and a leucine in the N-terminal region, but that both an arginine and two adjacent lysines in the C-terminal region of CopA3 also contribute. Collectively, these results provide insight into the interaction mechanism and the high selectivity of CopA3 for caspases.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.87-93
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• 2004

Dynamic modification of cytoplasmic and nuclear proteins by O-linked N-acetylglucosamine (O-GlcNAc) on Ser and Thr residues is ubiquitous in higher eukaryotes. And this modification may serve as a signaling mod-ification analogous to protein phosphorylation. Addition and cleavage of O-GlcNAc are catalyzed by O-linked GlcNAc transferase (OGT) and O-linked N-acety1glucosaminidase (O-GlcNAcase), respectively. Two types of human O-GlcNAcase gene were cloned and expressed as three fusion proteins in Escherichia coli. O-GlcNA-case activity showed in the order of thioredoxin fusion> $6{\times}His$ tag> GST fusion. O-GlcNAcase had enzy-matic activity against only ${\rho}$NP-GlcNAc of seven tested substrate analogs. Blast search revealed that O-GlcNAcase has two conserved domains, amino terminal hyaluronidase-like domain and carboxy terminal N-acetyltransferase domain. Extensive deletion studies were done to define catalytically important domains. The deletions of hyaluronidase-like domain and N-acetyltransferase domain abolished enzyme activity. But, N-ter-minal 55 amino acid deletion and C-terminal truncation showed lower activity. Based on deletion analysis, we suggest that hyaluronidase-like domain is essential for enzyme activity and carboxy terminal N-acetyltrans-ferase domain may be modulatory function.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.2
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• pp.133-140
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• 2001

PAP-I cDNA was synthesized from total RNA of Phytolacca americana leaves by RT-PCR, and then subcloned to recombinant vector pBluescript II SK-. Using PCR with primers designed in our laboratory, we could get the 9 deletion mutant PAP-I cDNA fragments. The first of the fragments was deleted by 66bp from immature N-terminal and then the rest were deleted by 90bp sequentially. Sequentially deletion mutant PAP-I cDNAs were inserted to pAc55M, on down-stream of gall promoter. Recombinant pAc55M was transformed to yeast cells, psy1 and the cells were spreaded on SC_urn-/glucose plate media. Colonies on SC_ura-/glucose plate were streaked on the same position of SC_ura-/glucose and SC_ura-/galactose plate, and we selected colonies growing on both plates, which carry non-cytotoxic deleted mutant PAP-I cDNA. We selected 4 deletion mutant PAP-I cDNAs which have not cytotoxicity.

• Journal of Genetic Medicine
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• v.11 no.1
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• pp.36-39
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• 2014

Chromosome 3 (3p) deletion syndrome is a rare genomic disorder caused by a deletion at the terminal end of the short arm of chromosome 3. The primary characteristics of the syndrome are delayed development, dysmorphic features, and several other congenital anomalies. Here, we describe the case of a 2-year-old Korean girl with typical features of 3p deletion syndrome, including dysmorphic facial features, low birth weight, developmental delay, growth and cognitive retardation, and congenital heart disease. This case represents the first report of 3p deletion syndrome in Korea. Although phenotypes can be variable among patients, a clinically recognizable pattern has been described for this genetic defect, and our report helps to identify other cases with 3p deletion syndrome from a clinical and genetic perspective.

• BMB Reports
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• v.49 no.6
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• pp.337-343
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• 2016

Understanding of trafficking, processing, and degradation mechanisms of amyloid precursor protein (APP) is important because APP can be processed to produce β-amyloid (Aβ), a key pathogenic molecule in Alzheimer's disease (AD). Here, we found that APP contains KFERQ motif at its C-terminus, a consensus sequence for chaperone-mediated autophagy (CMA) or microautophagy which are another types of autophagy for degradation of pathogenic molecules in neurodegenerative diseases. Deletion of KFERQ in APP increased C-terminal fragments (CTFs) and secreted N-terminal fragments of APP and kept it away from lysosomes. KFERQ deletion did not abolish the interaction of APP or its cleaved products with heat shock cognate protein 70 (Hsc70), a protein necessary for CMA or microautophagy. These findings suggest that KFERQ motif is important for normal processing and degradation of APP to preclude the accumulation of APP-CTFs although it may not be important for CMA or microautophagy.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.141-146
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• 2005

A new system for displaying proteins on the surface of Escherichia coli was developed using the Salmonella typhimurium outer membrane protein C (OmpC) as an anchoring motif. The C-terminal deletionfusion strategy was developed to fuse the polyhistidine peptides and green fluorescent protein (GFP) to the Cterminal of the truncated functional portion of OmpC. The polyhistidine peptides of up to 243 amino acids could besuccessfully displayed on the E. coli cell surface, which allowed recombinant E. coli to adsorb up to 34.2 μmol of Cd2+ per gram dry cell weight. The GFP could also be successfully displayed on the E. coli cell surface. These results suggest that the C-terminal deletion-fusion strategy employing the S. typhimurium OmpC as an anchoring motif provides a new efficient way for the display of large proteins on the surface of E. coli.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.193-198
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• 2008

ErmSF is one of the proteins which are produced by Streptomyces fradiae to avoid suicide by its autogenous macrolide antibiotic, tylosin and one of ERM proteins which are responsible for transferring the methyl group to $A_{2058}$ (Escherichia coli coordinate) in 23S rRNA, which reduces the affinity of MLS (macrolide-lincosamide-streptogramin B) antibiotics to 23S rRNA, thereby confers the antibiotic resistance on microorganisms ranging from antibiotic producers to pathogens. ErmSF contains an extra N-terminal end region (NTER), which is unique to ErmSF and 25% of amino acids of which is arginine known well to interact with RNA. Noticeably, arginine is concentrated in $^{58}RARR^{61}$ and functional role of each arginine in this motif was investigated through deletion and site-directed mutagenesis and the activity of mutant proteins in cell R60 and R61 was found to play an important role in enzyme activity through the study with deletion mutant up to R60 and R61. With the site-directed mutagenesis using deletion mutant of 1 to 59 (R60A, R61A, and RR60, 61AA), R60 was found more important than R61 but R61 was necessary for the proper activity of R60 and vice versa. And these amino acids were presumed to assume a secondary structure of $\alpha$-helix.