The structure of I_1-C region of the 5S rRNA from Pseudomonas alcaligenes : 5S rRNA from Pseudomonas alcaligenes

Koh, Moonjoo 조선대학교 부설 유전생물공학연구소 1994 유전생물공학연구지 Vol.4 No.-

리보솜의 구성성분인 Pseudomonas alcaligenes의 5S rRNA의 이차구조와 삼차상호작용을 화학적 변형법과 효소에 의한 절단 방법에 의하여 연구하였다. 특히 I_1-C 부분의 구조를 상세히 밝히기 위하여 특정한 부위에서 절단한 조각 5S rRNA의 염기들의 화학 변형의 정도를 여러가지 온도에서 조사하고 구조에 특이한 효소들을 사용하여 가수분해되는 자리들을 조사하여 그 결과들을 본래의 온전한 5S RNA에서 연구된 결과들과 비교검토하였다. 이를 위하여 5S rRNA를 특이한 부분에서 절단하는 방법을 찾아내었다. 3'-말단이 표지된 A_41-C_118의 조각 5S rRNA에서는 B줄기 부분의 C_60-U_63 부분이 I_2 고리 부분과 삼자 상호작용을 한다는 결과들을 관찰하였다. 5'-말단이 표지된 U_3-G_44 의 조각 5S rRNA에서는 구조에 특이한 효소들의 절단 자리들에 의하여 용액 중에서 머리핀 구조와 유사한 구조를 형성하며 특히 C_l7AG_19 부분이 C_31UG_33 부분과 염기쌍을 이룬다고 암시하는 결과를 얻었다. 이를 결과들로부터 조각 5S rRNA들의 모형을 제안하였다. The secondary structure of the 5S rRNA from Pseudomonas alcaligenes, the essential component of its ribosomes, was studied by the chemical modification of bases and the enzymatic cleavage methods. To verify the structure of the region of I1-C in detail, the degrees of the chemical modification of bases at various temperatures and the hydrolysis sites of the structure-specific enzymes for the fragments of 5S rRNA have been examined and compared the results with those of the full-length 5S rRNA. For the studies the method of site-specific fragmentation has been examined. It has been observed that C_60-U_63 of B helix is involved in a tertiary interaction with the region of I_2 loop in the fragmental 5S rRNA, A_4l-C_118, labelled at 3'-end. The structural features of the structure-specific enzymatic cleavage sites suggest that the fragmental 5S rRNA, U_3-G_44 labelled at 5'-end forms a hairpin structure in solution and C_17AG_19 makes base pairing with C_31UG_44. The models of the secondary structure of the fragments of the 5S rRNA consistent with these results have been proposed.

Metallothionein Induces Site-specific Cleavages in tRNAPhe

Moonjoo Koh,Jungyun Seon 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.6

It is known that metallothionein (MT) plays a role in the scavenging of free radicals, which is produced under various stress conditions. MT may function as an antioxidant that protects against oxidative damage of DNA, protein, and lipid induced by superoxide anion, hydrogen peroxide, hydroxyl radical, nitric oxide, and peroxynitrite. This study was undertaken to test the hypothesis that MT also protects from RNA damage induced by peroxynitrite, an important reactive nitrogen species that causes a diversity of pathological processes. A cell-free system was used. RNA damage was detected by the mobility of tRNAPhe in electrophoresis. Cleavages on tRNA were not induced by 3-morpholinosydnomine, which produces peroxynitrite directly. MT induced tRNA damage which was site specific.

Phytochelatin의 구조와 기능

고문주,이범규,김시욱 조선대학교 부설생명과학 연구소 1999 생명과학 연구 Vol.7 No.-

금속 이온이 존재하는 조건에서 성장하는 식물이나 효모에서 발견되는 금속-결합 펩티드는 글루타티온으로부터 유도되며 (γglu-cys)_(n)X 구조를 갖고 있다. 이런 펩티드를 피토켈라틴, γ-글루타밀 펩티드, 또는 부류 III 메탈로티오네인 (class III metallothionein)이라고 한다. 여기에서는 피토켈라틴의 일차구조, 금속-티올 배위결합, 생합성 및 관련된 효소, 금속내성과 항상성 같은 기능에 대하여 논의한다. Metal-binding peptides derived from glutathione were found in yeasts and plant species in the presence of added metal ions. The structure of these peptides was established as (γGlu-Cys)_(n)X. They have been designated as phytochelatins, γ-glutamyl peptides, and class III metallothioneins. In this paper, we reviewed phytochelatins in respect of the primary structure, metal-thiol coordinated cluster, biosynthesis and related enzymes, and functions such as metal tolerance and homeostasis.

The Effect of Metallothionein on the Activity of Superoxide Dismutase

Na, Soo-Mi,Koh, Moonjoo,Kim, Hee-Jeong,Kim, Si Wouk CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.1

To show the effect of MT on the activity of superoxide dismutase (SOD), metal-free apo-MT and native MTwere added to the assay system of SOD. The apo-MT was prepared by gel-filtration chromatography of the native form at low pH. We have used a well-known cytochrome c reduction assay of SOD as an assay ofsuperoxide scavenging rate. The reduction rate of cytochrome c by superoxide radicals was monitored at 550nm utilizing the xanthine-xanthine oxidase system as the source for O₂. Addition of MT increased the value of 1/ΔE, reciprocal absorbance change per minute, significantly at various concentration of superoxide, indicating MT increased the rate of breakdown of superoxide. But the addition of apo-MT increased the value of1/ΔE slightly. MT added to SOD assay system behaved as SOD activator, but apo-MT as SOD inhibitor. When MT was added to the assay system in the presence of fixed amount of apo-SOD and SOD, the breakdown rate of superoxide was increased. But apo-MT showed a lower effect than MT.

Characterization of Methylophaga sp. strain SK1 Cytochrome cL Expressed in Escherichia coli

김희곤,Trong Nhat Phan,장태사,Moonjoo Koh,김시욱 한국미생물학회 2005 The journal of microbiology Vol.43 No.6

Methylophaga sp. strain SK1 is a new restricted facultative methanol-oxidizing bacterium that was isolated from seawater. The aim of this study was to characterize the electron carriers involved in the methanol oxidation process in Methylophaga sp. strain SK1. The gene encoding cytochrome cL (mxaG) was cloned and the recombinant gene was expressed in Escherichia coli DH5 under strict anaerobic conditions. The recombinant cytochrome cL had the same molecular weight and absorption spectra as the wild-type cytochrome cL both in the reduced and oxidized forms. The electron flow rate from methanol dehydrogenase (MDH) to the recombinant cytochrome cL was similar to that from MDH to the wild-type cytochrome cL. These results suggest that recombinant cytochrome cL acts as a physiological primary electron acceptor for MDH.

메탈로티오네인의 기능

정혜광,김시욱,고문주 조선대학교 생명과학연구소 1998 생명과학 연구 Vol.6 No.-

For four decades after the original discovery of the small protein, metallothionein, its functional significance remains unclear. It is generally accepted that the principal roles of metallothioneins are detoxification of heavy metals and regulation of metabolism of essential trace metals. Nowadays there are emerging accounts on the function of metallothionein as an antioxidant. This manuscript reviews the structure, functions and induction of metallothioneins, especially focuses on the function as antioxidant. The medical implications of the free radical scavenging properties of metallothioneins are also discussed.

NiCR, CuCR 및 CdCR에 의한 $tRNA^{Phe}$의 화학적 절단

김희정,고문주,Kim, Hee-Joung,Koh, Moonjoo 대한화학회 1997 대한화학회지 Vol.41 No.10

Pseudomonadaceae 5S rRNAs의 이차구조의 일반모형

조봉래,이승주,심윤보,고문주,박인원,Bongrae Cho,Seung-Joo Lee,Yoonbo Sim,Moonjoo Koh,Inwon Park 대한화학회 1993 대한화학회지 Vol.37 No.3

Xanthomonas citri의 5S rRNA 의 구조 결정

조봉래,최명언,서세원,임자혜,고문주,박인원,Bongrae Cho,Myung-Un Choi,Se Won Seh,ahei Ihm,Moonjoo Koh,Inwon Park 대한화학회 1992 대한화학회지 Vol.36 No.3

Xanthomonas citri의 5S rRNA를 분리, 정제하여 효소적 방법과 화학적 방법으로 그 구조를 결정하였다. 이 5S rRNA는 119개의 누클레오티드로 구성되어 있으며 변형된 누클레오시드를 함유하지 않는다. 그리고 이 5S rRNA는 X. maltophilia의 것처럼 5'-말단에 가외의 우리딘 잔기를 하나 더 가지고 있다. 결정한 X. citri의 5S rRNA의 이차구조는 다른 원핵세포의 것들에 대해서 제안된 일반 모형들과 매우 유사하며 [De Wachter et al., Biochimie, 64, 311 (1982); Specht et al., Nucleic Acids Res., 18, 2215 (1990); Cho et al., Proceedings of the First Symposium on Biomolecules, p. 9 (1991)], 5개의 이중나선 줄기와 5개의 단일가닥 고리 그리고 2개의 내밀린 구조를 가진다. The structure of th 5S rRNA isolated from Xanthomonas citri was determined by enzymatic and chemical degradation methods. It consists of 119 nucleotides and contains no modified nucleosides. As does the 5S rRNA of X. maltophilia, it contains an additional uridine residue on the 5'-terminus. The secondary structure of the 5S rRNA from X. citri was almost identical to the generalized models proposed by many other workers [De Wachter et al., Biochimie, 64, 311 (1982); Specht et al., Nucleic Acids Res., 18, 2215 (1990); Cho et al., Proceedings of the First Symposium on Biomolecules, p. 9 (1991)]. The secondary structure of 5S rRNA from X. citri consists of five helices, five loops and two bulges. This 5S rRNA has a uridine residue at position 66 as a bulge.