Publications by authors named "Binh Van Le"

3 Publications

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Structural basis for the substrate selectivity of a HAD phosphatase from Thermococcus onnurineus NA1.

Biochem Biophys Res Commun 2015 May 6;461(1):122-7. Epub 2015 Apr 6.

Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea. Electronic address:

Proteins in the haloalkaloic acid dehalogenase (HAD) superfamily, which is one of the largest enzyme families, is generally composed of a catalytic core domain and a cap domain. Although proteins in this family show broad substrate specificities, the mechanisms of their substrate recognition are not well understood. In this study, we identified a new substrate binding motif of HAD proteins from structural and functional analyses, and propose that this motif might be crucial for interacting with hydrophobic rings of substrates. The crystal structure of TON_0338, one of the 17 putative HAD proteins identified in a hyperthermophilic archaeon, Thermococcus onnurineus NA1, was determined as an apo-form at 2.0 Å resolution. In addition, we determined the crystal structure TON_0338 in complex with Mg(2+) or N-cyclohexyl-2-aminoethanesulfonic acid (CHES) at 1.7 Å resolution. Examination of the apo-form and CHES-bound structures revealed that CHES is sandwiched between Trp58 and Trp61, suggesting that this Trp sandwich might function as a substrate recognition motif. In the phosphatase assay, TON_0338 was shown to have high activity for flavin mononucleotide (FMN), and the docking analysis suggested that the flavin of FMN may interact with Trp58 and Trp61 in a way similar to that observed in the crystal structure. Moreover, the replacement of these tryptophan residues significantly reduced the phosphatase activity for FMN. Our results suggest that WxxW may function as a substrate binding motif in HAD proteins, and expand the diversity of their substrate recognition mode.
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http://dx.doi.org/10.1016/j.bbrc.2015.03.179DOI Listing
May 2015

Structural and functional characterization of soluble endoglin receptor.

Biochem Biophys Res Commun 2009 Jun 5;383(4):386-91. Epub 2009 Mar 5.

Department of Molecular Cell Biology, Samsung Biomedical Research institute, Sungkyunkwan University School of Medicine, 300 Chunchun-Dong, Suwon 440-746, Republic of Korea.

Endoglin, an accessory membrane receptor of transforming growth factor-beta (TGF-beta)1, modulates the cellular response to TGF-beta via its interaction with type I and II TGF-beta receptors. It has been considered a promising target for the development of therapeutics and cancer markers. We have established stable CHO cell lines that efficiently secrete soluble endoglin (s-endoglin) fused with human growth hormone. Two oligomeric forms were observed in a homogeneous preparation of s-endoglin, as a dimer and a tetramer. The dimeric s-endoglin enhanced TGF-beta responsiveness in U937 cells, thus proving its potential for therapeutic applications. Small angle X-ray scattering (SAXS) experiments revealed elongated conformations of both dimeric and tetrameric s-endoglins in solution, suggesting that s-endoglin might undergo conformational adaptations upon TGF-beta binding. The current results provide important references and material for high-resolution structural studies and for medical applications of s-endoglin.
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http://dx.doi.org/10.1016/j.bbrc.2009.02.162DOI Listing
June 2009

Crystallization and preliminary X-ray studies of TON_1713 from Thermococcus onnurineus NA1, a putative member of the haloacid dehalogenase superfamily.

Acta Crystallogr Sect F Struct Biol Cryst Commun 2007 Dec 30;63(Pt 12):1048-50. Epub 2007 Nov 30.

Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea.

The haloacid dehalogenase (HAD) protein superfamily is one of the largest enzyme families and shows hydrolytic activity towards diverse substrates. Structural analyses of enzymes belonging to the HAD family are required to elucidate the molecular basis underlying their broad substrate specificity and reaction mechanism. For this purpose, TON_1713, a hypothetical protein from Thermococcus onnurineus that is a member of the HAD superfamily, was expressed in Escherichia coli, purified and crystallized at 295 K using 1.6 M magnesium sulfate as a precipitant. X-ray diffraction data were collected to 1.8 A resolution using a synchrotron-radiation source. The crystals belong to the triclinic space group P1, with unit-cell parameters a = 52.5, b = 65.8, c = 203.4 A, alpha = 71.1, beta = 79.9, gamma = 74.3 degrees.
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http://dx.doi.org/10.1107/S1744309107054747DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2344112PMC
December 2007
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