• 제목/요약/키워드: Macrocyclic structure

검색결과 68건 처리시간 0.023초

In vivo Imaging Biodistribution Profile of a New Macrocyclic Gadolinium Chelate as a Highly Stable Multifunctional MRI Contrast Agent

  • Sung, Bo Kyung;Jo, Yeong Woo;Chang, Yongmin
    • Investigative Magnetic Resonance Imaging
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    • 제23권1호
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    • pp.34-37
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    • 2019

  • Gadolinium contrast agents (CAs) are integral components of clinical magnetic resonance imaging (MRI). However, safety concerns have arisen regarding the use of gadolinium CAs, due to their association with nephrogenic systemic fibrosis (NSF). Furthermore, recently the long-term retention of $Gd^{3+}-based$ CAs in brains patients with normal renal function raised another possible safety issue. The safety concerns of $Gd^{3+}-based$ CAs have been based on the ligand structure of $Gd^{3+}-based$ CAs, and findings that $Gd^{3+}-based$ CAs with linear ligand structures showed much higher incidences of NSF and brain retention of CAs than $Gd^{3+}-based$ CAs with macrocyclic ligand structure. In the current study, we report the in vivo biodistribution profile of a new highly stable multifunctional $Gd^{3+}-based$ CA, with macrocyclic ligand structure (HNP-2006). MR imaging using HNP-2006 demonstrated a significant contrast enhancement in many different organs. Furthermore, the contrast enhanced tumor imaging using HNP-2006 confirmed that this new macrocyclic CA can be used for detecting tumor in the central nervous system. Therefore, this new multifunctional HNP-2006 with macrocyclic ligand structure shows great promise for whole-body clinical application.

  • https://doi.org/10.13104/imri.2019.23.1.34 인용 PDF KSCI

Solution-State Structure of Native Coenzyme F430 by NMR Methods

  • 원호식;Karl D. Olson;박지석;Ralph S. Wolfe;Dennis R. Hare;Michael F. Summers
    • Bulletin of the Korean Chemical Society
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    • 제16권7호
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    • pp.649-653
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    • 1995

  • Solution-state structure of native F430 was determined by using NMR methods and NMR-based distance geometry (DG) computations. Structures were generated with loose NOE-derived interproton distance restraints (2.0-2.5 Å, 2.0-3.5 Å and 2.0-4.5 Å for strong, medium, and weak NOE cross-peak intensities, respectively). 2D NOESY back-calculations of structures were subsequently carried out for establishing the consistence between experimental data and DG-model structures. The back-calculated 2D NOESY spectra of resulting DG structures were well consistent with experimental 2D NOESY spectra. Superposition of 20 independent structures with macrocyclic ring atoms and all atoms of F430 afforded pairwise root mean square deviations (RMSD) of 0.025-0.125 Å and 0.64-1.3 Å, respectively. The macrocyclic rings of structures are well converged to a unique conformation with saddle-shaped deformation whereas most of side chains are not converged. The average dihedral angle (N1-N2-N3-N4, 27.78±1.50°) of 20 DG-structures exhibits that the macrocyclic ring conformation is puckered as much as 12,13-diepimeric F430 (28.75±4.07°).

  • https://doi.org/10.5012/bkcs.1995.16.7.649 인용 PDF

Synthesis of α-oximinoketones, Precursor of CO2 Reduction Macrocyclic Coenzyme F430 Model Complexes

  • Kim, Gilhoon;Won, Hoshik
    • 한국자기공명학회논문지
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    • 제21권4호
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    • pp.139-144
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    • 2017

  • Ni(II) containing coenzyme F430 catalyzes the reduction of $CO_2$ in methanogen. Macrocyclic Ni(II) complexes with N,O shiff bases have been received a great attention since metal ions play an important role in the catalysis of reduction. The reducing power of metal complexes are supposed to be dependent on oxidoreduction state of metal ion and structural properties of macrocyclic ring moiety that can enhance electrochemical properties in catalytic process. Six different ${\alpha}$-oximinoketone compounds, precursor of macrocyclic ligands used in $CO_2$ reduction coenzyme F430 model complexes, were synthesized with yields over 90% and characterized by NMR. The molecular geometries of ${\alpha}$-oximinoketone analogues were fully optimized at Beck's-three-parameter hybrid (B3LYP) method in density functional theory (DFT) method with $6-31+G^*$ basis set using the ab initio program. In order to understand molecular planarity and substitutional effects that may enhance reducing power of metal ion are studied by computing the structure-dependent $^{13}C$-NMR chemical shift and comparing with experimental results.

  • https://doi.org/10.6564/JKMRS.2017.21.4.139 인용 PDF KSCI

Electronic Structures of a Macrocyclic Fulleropyrrolidine

  • 황선구;이종명;전일철
    • Bulletin of the Korean Chemical Society
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    • 제17권12호
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    • pp.1112-1117
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    • 1996

  • The electronic structures of twenty-seven isomers of a macrocyclic fulleropyrrolidine are investigated with semi-empirical extended Huckel (EH) molecular orbital method. The geometry of each isomer is determined by the molecular mechanics and dynamics methods based on UFF (universal force field) empirical force field. The calculated geometries, such as the carbon-carbon distances of the fullerene moiety, are in good agreement with those of related fullerene derivatives. The EH calculation shows that the formation of macrocyclic pyrrolidine ring on fullerene moiety results in the reduction of the HOMO-LUMO energy gap. From the graphical analysis of the DOS (density of states), PDOS (projected DOS), and MOOP (molecular orbital overlap population) curves, we can find that this reduction is due to splitting of the HOMO of fullerene moiety, which results from the symmetry-breaking and the distortion of the buckminsterfullerene framework from its ideal icosahedral structure.

  • https://doi.org/10.5012/bkcs.1996.17.12.1112 인용 PDF