• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.1104-1107
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• 2020

The N-terminal domain of the Pseudomonas sp. FB15 phytase increases low-temperature activity and catalytic efficiency. In this study, the 3D structure of the N-terminal domain was predicted and substitutions for the amino acid residues of the region assumed to be the active site were made. The activity of mutants, in which alanine (A) was substituted for the original residue, was investigated at various temperatures and pH values. Significant differences in enzymatic activity were observed only in mutant E263A, suggesting that the amino acid residue at position 263 of the N-terminal domain is important in enzyme activity.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.234-242
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• 2008

To identify low temperature-induced genes of wheat chromosome substitution line 5D, suppression subtractive hybridization (SSH) was performed with mRNAs from leaf samples that treated with low temperature ($4^{\circ}C$). A cDNA library was constructed using mRNA isolated from wheat chromosome substitution line 5D leaves treated with low temperature ($4^{\circ}C$). The nucleotide and deduced amino acid sequences of the putative gene products were compared. wfr-9 and wfr-32 showed identity over 90% related to vernalization gene. Other two genes, wfr-77 and wfr-83 which is related to freezing-resistant gene have also identity over 90%. This result suggest that those genes may be transcribed into antifreeze proteins which are accumulated within leaf apoplasts, when wheat chromosome substitution line 5D is acclimated during low temperature treatment.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.779-779
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• 2005

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.244.2-244.2
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• 2011

We introduce a novel and robust method for the preparation of nanocomposite multilayers, which allows the excellent photoluminescent (PL) properties as well as the accurate control over the composition and dimensions of multilayers. By exchanging the oleic acid stabilizers of CdSe@ZnS quantum dots (QDs) synthesized in organic solvent with 2-bromo-2-methylpropionic acid (BMPA) in the same solvent, these nanoparticles were be alternately deposited by nucleophilic substitution reaction with highly branched poly(amidoamine) dendrimer (PAMA) through layer-by-layer (LbL) assembly process. Our approach does not need to be transformed into the water-dispersible nanoparticles with electrostatic or hydrogen-bonding groups, which can deteriorate their inherent properties, for the built-up of multilayers. The nanocomposite multilayers including QDs exhibited the strong PL properties achieving densely packed surface coverage as well as long-term PL stability under atmospheric conditions in comparison with those of conventional LbL multilayers based on electrostatic interaction. Furthermore, we demonstrate that the flexible multilayer films with optical properties can be easily prepared using nucleophilic substitution reaction between bromo and amino groups in organic media. This robust and tailored method opens a new route for the design of functional film devices based on nanocomposite multilayers.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.4
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• pp.464-470
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• 2014

One of the most important traits for both animal science and livestock production is the number of offspring for a species. This study was performed to identify differentially evolved genes and their distinct functions that influence the number of offspring at birth by comparative analysis of eight monotocous mammals and seven polytocous mammals in a number of scopes: specific amino acid substitution with site-wise adaptive evolution, gene expansion and specific orthologous group. The mutually exclusive amino acid substitution among the 16 mammalian species identified five candidate genes. These genes were both directly and indirectly related to ovulation. Furthermore, in monotocous mammals, the EPH gene family was found to have undergone expansion. Previously, the EPHA4 gene was found to positively affect litter size in pigs and supports the possibility of the EPH gene playing a role in determining the number of offspring per birth. The identified genes in this study offer a basis from which the differences between monotocous and polytocous species can be studied. Furthermore, these genes may harbor some clues to the underlying mechanism, which determines litter size and may prove useful for livestock breeding strategies.

• BMB Reports
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• v.43 no.6
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• pp.427-431
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• 2010

Cyt2Aa2 is a mosquito-larvicidal protein produced as a 29 kDa crystalline protoxin from Bacillus thuringiensis subsp. darmstadiensis. To become an active toxin, proteolytic processing is required to remove amino acids from its N- and C-termini. This study aims to investigate the functional role of amino acid residues on the N-terminal ${\beta}1$ and C-terminal ${\alpha}F$ of Cyt2Aa2 protoxin. Mutant protoxins were constructed, characterized and compared to the wild type Cyt2Aa2. Protein expression data and SDS-PAGE analysis revealed that substitution at leucine-33 (L33) of ${\beta}1$ has a critical effect on dimer formation and structural stability against proteases. In addition, amino acids N230 and I233-F237 around the C-terminus ${\alpha}F$ demonstrated a crucial role in protecting the protoxin from proteolytic digestion. These results suggested that ${\beta}1$ and ${\alpha}F$ on the Nand C-terminal ends of Cyt2Aa2 protoxin play an important role in the molecular interaction and in maintaining the structural stability of the protoxin.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2531-2534
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• 2013

• The Korean Journal of Pesticide Science
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• v.7 no.4
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• pp.239-247
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• 2003

This experiment was carried out to study the resistant mechanism of sulfonylurea(SU) herbicides to Monochoria korsakowii occurring in the rice fields of Korea. The activity of acetolactate synthase(ALS), absorption and translocation of $[^{14C}]$bensulfuron-methyl, and DNA sequence of ALS genes were studied. The apparent SU resiatance to Monochoria korsakowii was confirmed in greenhouse testes. Fresh weight accumulation$(GR_{50})$ in the resistant biotype was about 5- to 64-fold higher in the presence of six SU herbicides compared to the susceptible biotype. The ALS activity isolated from the resistant biotype to herbicides tested was less sensitive than that of susceptible biotype. The concentration of herbicide required for 50% inhibition of ALS activity$(I_{50})$ was 14- to 76-fold higher as compared to the susceptible biotype. No differences were observed in the rates of $[^{14C}]$bensulfuron uptake and translocation. However, the DNA sequence from the resistant biotype differed from that of the susceptible biotype by single nucleotide substitution at three amino acid each in the middle region excluding the ends of ALS genes. We found three point mutations causing substitution of serine for threonine at amino acid 168, arginine for histidine at amino acid 189, and a aspartic acid for phenylalanine at amino acid 247, respectively, in the resistant biotype.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.325-330
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• 2007

RNase E is an essential Escherichia coli endoribonuclease that plays a major role in the decay and processing of a large fraction of RNAs in the cell and expression of N-terminal domain consisted of 1-498 amino acids (N-Rne) is sufficient to support normal cellular growth. By utilizing these properties of RNase E, we developed a genetic system to screen for amino acid substitutions in the catalytic domain of the protein (N-Rne) that lead to various phenotypes. Using this system, we identified three kinds of mutants. A mutant N-Rne containing amino acid substitution in the S1 domain (I6T) of the protein was not able to support survival of E. coli cells, and another mutant N-Rne with amino acid substitution at the position 488 (R488C) in the small domain enabled N-Rne to have an elevated ribonucleolytic activity, while amino acid substitution in the DNase I domain (N305D) only enabled N-Rne to support survival of E. roli cells when the mutant N-Rne was over-expressed. Analysis of copy number of ColEl-type plasmid revealed that effects of amino acid substitution on the ability of N-Rne to support cellular growth stemmed from their differential effects on the ribonucleolytic activity of N-Rne in the cell. These results imply that the genetic system developed in this study can be used to isolate mutant RNase E with various phenotypes, which would help to unveil a functional role of each subdomain of the protein in the regulation of RNA stability in E. coli.

• Mycobiology
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• v.48 no.2
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• pp.148-152
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• 2020

We investigated the antifungal susceptibilities and the cyp51 mutant strains among Aspergillus fumigatus clinical isolates obtained from 10 university hospitals in Korea. Of the 84 isolates examined, two itraconazole-resistant isolates were found with no amino acid substitution in the cyp51A/cyp51B genes. However, 19 (23.2%) azole-susceptible isolates harbored amino acid substitutions: Nine isolates harbored one to five mutations in cyp51A with high polymorphism, and 11 isolates exhibited the same Q42L mutation in cyp51B. Overall, a low azole resistance rate and high frequency of cyp51A/cyp51B amino acid substitutions were observed in the azole-susceptible A. fumigatus isolates in Korea.