Yoonjeong Kim

Kyungpook National University, Daikyū, Daegu, South Korea

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Publications (3)13.72 Total impact

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    ABSTRACT: Considerable attention has recently been paid to the N-Myc downstream-regulated gene (NDRG) family because of its potential as a tumor suppressor in many human cancers. Primary amino acid sequence information suggests that the NDRG family proteins may belong to the α/β-hydrolase (ABH) superfamily; however, their functional role has not yet been determined. Here, we present the crystal structures of the human and mouse NDRG2 proteins determined at 2.0 and 1.7 Å resolution, respectively. Both NDRG2 proteins show remarkable structural similarity to the ABH superfamily, despite limited sequence similarity. Structural analysis suggests that NDRG2 is a nonenzymatic member of the ABH superfamily, because it lacks the catalytic signature residues and has an occluded substrate-binding site. Several conserved structural features suggest NDRG may be involved in molecular interactions. Mutagenesis data based on the structural analysis support a crucial role for helix α6 in the suppression of TCF/β-catenin signaling in the tumorigenesis of human colorectal cancer, via a molecular interaction.
    No preview · Article · Apr 2011 · Journal of Biological Chemistry
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    ABSTRACT: Quorum sensing has been implicated as an important global regulatory system controlling the expression of numerous virulence factors in bacterial pathogens. SmcR, a homologue of Vibrio harveyi LuxR, has been proposed as a quorum-sensing master regulator of Vibrio vulnificus, an opportunistic human pathogen. Previous studies demonstrated that SmcR is essential for the survival and pathogenesis of V. vulnificus, indicating that inhibiting SmcR is an attractive approach to combat infections by the bacteria. Here, we determined the crystal structure of SmcR at 2.1 Å resolution. The protein structure reveals a typical TetR superfamily fold consisting of an N-terminal DNA binding domain and a C-terminal dimerization domain. In vivo and in vitro functional analysis of the dimerization domain suggested that dimerization of SmcR is vital for its biological regulatory function. The N-terminal DNA recognition and binding residues were assigned based on the protein structure and the results of in vivo and in vitro mutagenesis experiments. Furthermore, protein-DNA interaction experiments suggested that SmcR may have a sophisticated mechanism that enables the protein to recognize each of its many target operators with different affinities.
    Preview · Article · Feb 2010 · Journal of Biological Chemistry
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    ABSTRACT: Triphenylmethane dyes are aromatic xenobiotic compounds that are widely considered to be one of the main culprits of environmental pollution. Triphenylmethane reductase (TMR) from Citrobacter sp. strain KCTC 18061P was initially isolated and biochemically characterized as an enzyme that catalyzes the reduction of triphenylmethane dyes. Information from the primary amino acid sequence suggests that TMR is a dinucleotide-binding motif-containing enzyme; however, no other functional clues can be derived from sequence analysis. We present the crystal structure of TMR in complex with NADP+ at 2.0-Å resolution. Despite limited sequence similarity, the enzyme shows remarkable structural similarity to short-chain dehydrogenase/reductase (SDR) family proteins. Functional assignments revealed that TMR has features of both classic and extended SDR family members and does not contain a conserved active site. Thus, it constitutes a novel class of SDR family proteins. On the basis of simulated molecular docking using the substrate malachite green and the TMR/NADP+ crystal structure, together with site-directed mutagenesis, we have elucidated a potential molecular mechanism for triphenylmethane dye reduction.
    Full-text · Article · Oct 2008 · Journal of Biological Chemistry

Publication Stats

57 Citations
13.72 Total Impact Points


  • 2010-2011
    • Kyungpook National University
      • School of Food Science and Biotechnology
      Daikyū, Daegu, South Korea
  • 2008
    • Korea Research Institute of Bioscience and Biotechnology KRIBB
      • Systems Microbiology Research Center
      Daiden, Daejeon, South Korea