• Bulletin of the Korean Chemical Society
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• 제3권3호
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• pp.110-115
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• 1982

Thermochemistry and photochemistry of picolyl chlorides were studied. The thermal reaction of 2-picolyl chloride in benzene afforded intermolecular condensation product. In the case of 3-picolyl chloride, this type of the reaction did not occur, but polymers were obtained. A cyclic hexamer, suggested by a molecular model, was not formed because of the steric strain and low reactivity. The thermal reaction of 4-picolyl chloride gave a cyclic hexamer as well as a polymer. The cyclic hexamer, identified by NMR spectrum, showed ${\lambda}_{max}$ at 460 nm. The cyclic hexamer was cloven to the linear structure. Photolysis of 2-picolyl chloride at 253.7 nm gave a para-isomer followed by polymerization. When a methyl hydrogen of 2-methylpyridine is substituted by $CH_3O$, iso-PrO, and EtO group, the photoisomerization to the corresponding anilines or para-substituted pyridines did not occur within the range of the time used for 2-picolyl chloride. Thermolysis of picolyl chlorides in an acidic methanol solution did not afford any product.

• 대한화학회지
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• 제67권5호
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• pp.348-352
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• 2023

p97, a universally conserved AAA+ ATPase, holds a central position in the ubiquitin-proteasome system, orchestrating myriad cellular activities with significant therapeutic implications. This protein primarily interacts with a diverse set of adaptor proteins through its N-terminal domain (NTD), which is structurally located at the periphery of the D1 hexamer ring. While there have been numerous structural elucidations of p97 complexed with adaptor proteins, the stoichiometry has remained elusive. In this work, we present the crystal structure of the p97-N/D1 hexamer bound to the FAF1-UBX domain at a resolution of 3.1 Å. Our findings reveal a 6:6 stoichiometry between the p97 hexamer and FAF1-UBX domain, deepening our understanding from preceding structural studies related to p97-NTD and UBX domain-containing proteins. These insights lay the groundwork for potential therapeutic interventions addressing cancer and neurodegenerative diseases.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2595-2602
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• 2009

Hexamer cluster of N,N-dimethylformamide(DMF) based on the crystal structure was investigated for the equilibrium structure, the stabilization energies, and the vibrational properties in the density functional force field. The geometry (point group $C_i$) of fully optimized hexamer clustered DMF shows quite close similarity to the crystal structure weakly intermolecular hydrogen bonded each other. Stretching force constants for intermolecular hydrogen bonded methyl and formyl hydrogen atoms with nearby oxygen atom, methyl C–H${\cdots}$O and formyl C–H${\cdots}$O, were obtained in 0.055 $\sim$ 0.11 and $\sim$ 0.081 mdyn/$\AA$, respectively. In-plane bending force constants for hydrogen bonded methyl hydrogen atoms were in 0.25 $\sim$ 0.33, and for formyl hydrogen $\sim$ 0.55 mdynÅ. Torsion force constants through hydrogen bonding for methyl hydrogen atoms were in 0.038 $\sim$ 0.089, and for formyl hydrogen atom $\sim$ 0.095 mdynÅ. Calculated Raman and infrared spectral features of single and hexamer cluster represent well the experimental spectra of DMF obtained in the liquid state. Noncoincidence between IR and Raman frequency positions of stretching C=O, formyl C–H and other several modes was interpreted in terms of the intermolecular vibrational coupling in the condensed phase.

• Bulletin of the Korean Chemical Society
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• 제21권6호
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• pp.555-556
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• 2000

• 대한화학회지
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• 제26권5호
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• pp.304-309
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• 1982

Chlorophyll-a(chl-a)와 chlorophyll-b(chl-b)를 pyridine을 포함한 실리콘의 dimer, hexamer에 결합시킨 물질은 중합체의 pyridine 농도와 chl-a의 농도의 비가 1:1일 때 가장 큰 에너지 전이를 나타냈으며 chl-b와 실리콘 중합체는 가장 큰 들뜬 에너지를 나타냈다.

• Bulletin of the Korean Chemical Society
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• 제13권3호
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• pp.223-225
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• 1992

• 한국동물학회지
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• 제39권3호
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• pp.307-316
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• 1996

담배나방 (Helicoverpa assulta)의 발생기간 중 존재하는 major haemolyruph protein (MHP)을 확인하였으며, 그 발생에 따른 변화상 및 물리화학적 특성을 조사하였다. MHP는 유충-용-성충의 발생단계에서 확인되었으며, 그 함량은 유충의 성장에 따라 증가하여 용기와 성충기 동안에도 높게 유지되고 용초기와 성충 초기에서 일시적인 감소를 보여, 총 혈림프 단백질의 농도 변화와 유사한 변화양상을 보였다. ammonium sulfate precipitation, gel filtration 그리고 ion exchange chromatography를 통해 정제한 MHP의 전기영동 분석 결과, 단일 구성소 단위 (69 kDa)가 hexamer를 이룬 분자량 414kDa의 glycolipoprotein (pI 5.9)인 것으로 확인되었다. MHP의 아미노산 조성에 있어서 18.27 mole % 의 tryptophan, 7.47 mole % 의 tyrosine and 6.51 mole % 의 phenylalanine이 검출되어 다른 곤충류의 저단백질들에 비해 비교적 높은 aromatic amino acid의함량을 보였다. 지방체, 장, 말피기관 단백질의 전기영동 및 이들 단백질과 anti-MHP간의 immunodiffusion test 결과 MHP는 지방체에 존재하고 있음이 확인되었다.

• Bulletin of the Korean Chemical Society
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• 제13권4호
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• pp.345-346
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• 1992

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권1호
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• pp.23-34
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• 2004

Escherichia coli transcription termination factor Rho catalyzes the unwinding of RNA/DNA duplex in reactions that are coupled to ATP binding and hydrolysis. Fluorescence stopped-flow methods using ATP and the fluorescent 2'(3')-O-( N-methylanthraniloyl) derivatives (mant-derivatives) of ATP and ADP were used to probe the kinetics of nucleotide binding to and dissociation from the Rho-RNA complex. Presteady state nucleotide binding kinetics provides evidence for the presence of negative cooperativity in nucleotide binding among the multiple nucleotide binding sites on Rho hexamer. The binding of the first nucleotide to the Rho-RNA complex occurs at a bimolecular rate of 3.6${\times}$10$\^$6/ M$\^$-1/ sec$\^$-1/ whereas the second nucleotide binds at a slower rate of 4.7${\times}$10$\^$5/ M$\^$-1/ sec$\^$-1/ at 18$^{\circ}C$, RNA complexed with Rho affects the kinetics of nucleotide interaction with the active sites through conformational changes to the Rho hexamer, allowing the incoming nucleotide to be more accessible to the sites. Adenine nucleotide binding and dissociation is more favorable when RNA is bound to Rho, whereas ATP binding and dissociation step in the absence of RNA occurs significantly slower, at a rate ∼70- and ∼40-fold slower than those observed with the Rho-RNA complex, respectively.

• Reproductive and Developmental Biology
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• 제36권3호
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• pp.193-198
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• 2012

This study was to examine expression of the recombinant full-length adiponectin (recombinant adiponectin) in insect ovarian cell culture system and to characterize structural properties of the recombinant adiponectin secreted in medium. Gene construct encoding the recombinant adiponectin contained N-terminal collagen-like domain (110 Amino Acids, AAs), C-terminal globular domain (137 AAs) and C-terminal peptides for detection with V5 antibody (26 AAs included adaptor peptide) and purification using the 6xHis tag (6 AAs). The approximate molecular weight of the product (monomer) was 35 kDa. Molecular mass species of the expressed recombinant adiponectin were monomer (~35 kDa), dimer (~70 kDa), trimer (~105 kDa) and hexamer (~210 kDa). The major secreted species were the LMW forms, such as monomer, dimer, and trimer. There was MMW of hexamer as minor form. HMW multimers (~300 kDa) were shown as a tracer or not detected on the SDS-PAGE in several experiments (data not shown). The multimer forms in this study were not compatible to those in animal or human serum and adipose tissue by other researcher's study in which the major multimer forms were HMW. By protein denaturing experiments with reducing reagent (${\beta}$-MeOH), anionic detergent (SDS) and heat ($95^{\circ}C$) on the SDS-PAGE, not all adiponectin multimers seemed to have disulfide bond linked structure to form multimers. The recombinant adiponectin which expressed in insect ovarian cell culture system seemed to have the limitation as full physiological regulator for the application to animal and human study.