• 생명과학회지
• /
• 제23권7호
• /
• pp.847-853
• /
• 2013

원추리속 식물은 초본류이며 이 속의 일부 종은 약용으로 중요하다. 이 속의 8개 분류군에 대해 엽록체의 rps16-trnK 부위로 계통관계를 평가하였다. 배당된 서열은 원추리(H. aurantiaca)에서 729 핵산 수로 가장 적었으며 왕원추리(H. fulva var. kwanso)에서 742 핵산 수로 가장 많았다. 그 차이는 염기 삽입에 기인하였다. 비록 일부 인델(indel)과 20개 염기의 삽입이 발견되었지만 서열 내 변이는 염기 치환이 많았다. rps16 - trnK에 의한 한국내 원추리속 분류군들은 높은 지지도로 잘 분리되었다. 애기원추리(H. minor)와 홍도원추리(H. littorea)는 높은 지지도로 같은 분지군을 형성하였으며 이 분지군은 노랑원원추리와 자매군을 형성하였다. 염색체의 수는 기존 보고된 RAPD의 결과와는 일치하지 않으나 본 연구와는 일치하였다.

• Molecules and Cells
• /
• 제20권3호
• /
• pp.392-400
• /
• 2005

The genes encoding the DNA gyrase A (GyrA) and B subunits (GyrB) of Methylovorus sp. strain SS1 were cloned and sequenced. gyrA and gyrB coded for proteins of 846 and 799 amino acids with calculated molecular weights of 94,328 and 88,714, respectively, and complemented Escherichia coli gyrA and gyrB temperature sensitive (ts) mutants. To analyze the role of type II topoisomerases in the intrinsic quinolone resistance of methylotrophic bacteria, the sequences of the quinolone resistance-determining regions (QRDRs) in the A subunit of DNA gyrase and the C subunit (ParC) of topoisomerase IV (Topo IV) of Methylovorus sp. strain SS1, Methylobacterium extorquens AM1 NCIB 9133, Methylobacillus sp, strain SK1 DSM 8269, and Methylophilus methylotrophus NCIB 10515 were determined. The deduced amino acid sequences of the QRDRs of the ParCs in the four methylotrophic bacteria were identical to that of E. coli ParC. The sequences of the QRDR in GyrA were also identical to those in E. coli GyrA except for the amino acids at positions 83, 87, or 95. The $Ser^{83}$ to Thr substitution in Methylovorus sp. strain SS1, and the $Ser^{83}$ to Leu and $Asp^{87}$ to Asn substitutions in the three other methylotrophs, agreed well with the minimal inhibitory concentrations of quinolones in the four bacteria, suggesting that these residues play a role in the intrinsic susceptibility of methylotrophic bacteria to quinolones.

• Journal of Microbiology
• /
• 제45권5호
• /
• pp.418-421
• /
• 2007

The nucleotide at position 791(G791) of E. coli 16S rRNA was previously identified as an invariant residue for ribosomal function. In order to characterize the functional role of G791, base substitutions were introduced at this position, and mutant ribosomes were analyzed with regard to their protein synthesis ability, via the use of a specialized ribosome system. These ribosomal RNA mutations attenuated the ability of ribosomes to conduct protein synthesis by more than 65%. A transition mutation (G to A) exerted a moderate effect on ribosomal function, whereas a transversion mutation (G to C or U) resulted in a loss of protein synthesis ability of more than 90%. The sucrose gradient profiles of ribosomes and primer extension analysis showed that the loss of protein-synthesis ability of mutant ribosomes harboring a base substitution from G to U at position 791 stems partially from its inability to form 70S ribosomes. These findings show the involvement of the nucleotide at position 791 in the association of ribosomal subunits and protein synthesis steps after 70S formation, as well as the possibility of using 16S rRNA mutated at position 791 for the selection of second-site revertants in order to identify ligands that interact with G791 in protein synthesis.

• 한국양식학회지
• /
• 제22권1호
• /
• pp.79-82
• /
• 2009

한국 고유종인 각시붕어 R. uyekii와 떡납줄갱이 R. notatus로부터 유도된 정교배 및 상반교배 잡종어류의 분자생물학적 동정을 위하여 핵에서 encoding되는 RAG-1 유전자의 염기서열 분석을 실시하였다. 분석된 863 bp의 염기서열 중 각시붕어와 떡납줄갱이 사이에는 총 13개의 위치에서 염기서열 변이가 탐색되었다. 잡종어류의 RAG-1 유전자 염기서열을 분석한 결과 모계와 부계의 염기서열 차이를 보인 13개의 변이 부분에서 부모의 염기서열을 다같이 반영하는 double peaks 패턴을 보였으나 정교매체(UN 유전형)와 상반교배체(NU 유전형) 간의 염기서열 차이는 관찰되지 않았다.

• Bulletin of the Korean Chemical Society
• /
• 제30권7호
• /
• pp.1547-1552
• /
• 2009

Sphingomonas chungbukensis DJ77 has the ability to produce large quantities of an extracellular polysaccharide that can be used as a gelling agent in the food and pharmaceutical industries. We identified, cloned and expressed the UDP-glucose dehydrogenase gene of S. chungbukensis DJ77, and characterized the resulting protein. The purified UDP-glucose dehydrogenase (UGDH), which catalyzes the reversible conversion of UDP-glucose to UDPglucuronic acid, formed a homodimer and the mass of the monomer was estimated to be 46 kDa. Kinetic analysis at the optimal pH of 8.5 indicated that the $K_m\;and\;V_{max}$ for UDP-glucose were 0.18 mM and 1.59 mM/min/mg, respectively. Inhibition assays showed that UDP-glucuronic acid strongly inhibits UGDH. Site-directed mutagenesis was performed on Gly9, Gly12 Thr127, Cys264, and Lys267. Substitutions of Cys264 with Ala and of Lys267 with Asp resulted in complete loss of enzymatic activity, suggesting that Cys264 and Lys267 are essential for the catalytic activity of UGDH.

• BMB Reports
• /
• 제33권6호
• /
• pp.519-524
• /
• 2000

NF1 proteins are a family of DNA binding proteins which consist of two separate domains, N-terminal DNA binding domain and C-terminal transcription activation domain. The N-terminal 220 amino acids are highly conserved and are also known to mediate dimerization of NF1 proteins. The C-terminal regions of different type of NF1 proteins are heterogeneous and responsible for transcriptional activation. In this study, we tested the interaction between different domains of rat NF1-A protein by yeast two hybrid analysis and observed the interaction between C-terminal regions of NF1-A which do not contain the N-terminal dimerization domain. Our results showed that the C-terminal region of rat NF1-A between residues 231 and 509 strongly interacted not only with itself, but also with human NF1/CTF1 which is a different type of NF1. When the C-terminal region was divided into two fragments, one from residue 231 to 447 and the other from 448 to 509, the two fragments were able to interact with the C-terminal region of NF1-A significantly. This indicates that both fragments contain independent interaction domains. Analysis of the interactions with alanine substituted fragments showed that substitutions of the heptasequence, SPTSPTY of NF1-A, affected interaction between NF1 proteins. Our results strongly suggest that C-terminal regions may also be important for the formation of homo- and heterodimers in addition to the N-terminal dimerization domain. Also, the heptasequence motif may play some roles in dimer formation.

• BMB Reports
• /
• 제41권8호
• /
• pp.604-608
• /
• 2008

1-Nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide are oxidative metabolites that are responsible for the mutagenicity of 1-nitropyrene. In this study, the mutation spectra induced by oxidative metabolites in human cells were determined using a shuttle vector assay. The mutation frequencies induced by 1-nitropyrene 9,10-oxide were 2-3 times higher than those induced by 1-nitropyrene 4,5-oxide. The base substitutions induced by 1-nitropyrene 4,5-oxide were $G{\rightarrow}A$ transitions, $G{\rightarrow}C$ transversions, and $G{\rightarrow}T$ transversions. In the case of 1-nitropyrene 9,10-oxide, $G{\rightarrow}A$ transitions, $G{\rightarrow}T$ transversions, $A{\rightarrow}G$ transitions and $G{\rightarrow}C$ transversions were observed. Most base substitution mutations induced by oxidative metabolites occurred at the guanine sites in the supF gene. These sequence-specific hot spots were commonly identified as 5'-GA sequences for both metabolites. On the other hand, the sequence-specific hot spots at the adenine sites were identified as 5'-CAC sequences for 1-nitropyrene 9,10-oxide. These results suggest that the oxidative metabolites of 1-nitropyrene induce sequence-specific DNA mutations at the guanine and adenine sites at high frequency.

• 대한기관식도과학회지
• /
• 제18권2호
• /
• pp.45-48
• /
• 2012

Background Neoplastic vessels tend to proliferate on the surface of malignant lesions in the aerodigestive tract. So, superficial malignant lesions can be detected earlier by enhancing mucosal vascular clarity. To enhance mucosal vascular clarity on endoscopic image, we developed an image processing algorithm of RGB (red-green-blue) channel substitution image (CSI). Methods Each pixel in original white light image (WLI) has its own value of red, green and blue channel. Various combinations of RGB channel substitution was tried on original WLI. Results To make superficial blood vessels darker than brighter background mucosa, in the CSI algorithm, RGB value in each pixel of WLI is substituted; red value to green one, green value to blue one. There was a good contrast between superficial mucosal vessels and background brighter mucosa in the CSI image. Conclusion By RGB CSI algorithm, WLI could be successfully converted to new images with enhanced mucosal vascular clarity. Using RGB CSI algorithm could provide added vascular visibility on original WLI.

• Molecules and Cells
• /
• 제27권2호
• /
• pp.183-190
• /
• 2009

The plasma membrane-localized BRASSINOSTEROID-INSENSITIVE1 (BRI1) and BRI1-ASSOCIATED KINASE1 (BAK1) are a well-known receptor pair involved in brassinosteroids (BR) signaling in Arabidposis. The formation of a receptor complex in response to BRs and the subsequent activation of cytoplasmic domain kinase activity share mechanistic characteristics with animal receptor kinases. Here, we demonstrate that BRI1 and BAK1 are BR-dependently phosphorylated, and that phosphorylated forms of the two proteins persist for different lengths of time. Mutations of either protein abolished phosphorylation of the counterpart protein, implying transphosphorylation of the receptor kinases. To investigate the specific amino acids critical for formation of the receptor complex and activation of BAK1 kinase activity, we expressed several versions of BAK1 in yeast and plants. L32E and L46E substitutions resulted in a loss of binding of BAK1 to BRI1, and threonine T455 was essential for the kinase activity of BAK1 in yeast. Transgenic bri1 mutant plants overexpressing BAK1(L46E) displayed reduced apical dominance and seed development. In addition, transgenic wild type plants overexpressing BAK1(T455A) lost the phosphorylation activity normally exhibited in response to BL, leading to semi-dwarfism. These results suggest that BAK1 is a critical component regulating the duration of BR efficacy, even though it cannot directly bind BRs in plants.

• 미생물학회지
• /
• 제42권3호
• /
• pp.230-234
• /
• 2006

레트로바이러스의 합포체(syncytia)형성 기작 연구를 위해 합포체 형성을 유도하는 새로운 ecotropic 마우스레트로바이러스(Friend murine leukemia virus)변이주를 실험에 사용하였다. 마우스레트로바이러스의 외막에 존재하는 당단백질 중 수용체와 결합하는 부위의 아미노산을 변화시키면 합포체를 형성할 수 있음이 이미 밝혀졌다. 본 연구에서는 합포체 유도 마우스레트로바이러스 외막 당단백질을 가진 pseudotype 레트로바이러스 벡터로 부터도 이러한 융합 현상이 일어날 수 있는지 알아보았다. 마우스 세포주인 M. dunni에 pseudotype 바이러스를 감염시킨 결과 레트로바이러스 벡터 매개에 의한 바이러스-세포간 융합 현상은 일어나지 않았다. 이러한 실험결과는 합퐁체 형성이 바이러스 복제가 가능한 합포체 유도 마우스레트로바이러스에만 일어남을 나타낸다. 또한 ecotropic 마우스레트로바이러스 수용체의 농도와 막 융합과의 상관관계도 없는 것으로 밝혀졌다.