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Zhang W.,Uppsala University | Moden O.,Uppsala University | Tars K.,Biomedical Research and Study Center | Mannervik B.,Uppsala University | Mannervik B.,University of Stockholm
Chemistry and Biology | Year: 2012

Glutathione transferase (GST) A2-2 is the most efficient human enzyme in the biotransformation of the prodrug azathioprine (Aza). The activation of Aza has therapeutic potential for possible use of GSTs in targeted enzyme-prodrug treatment of diseases. Based on the assumed catalytic mechanism and computational docking of Aza to the active site of the enzyme, active-site residues were selected for construction of focused mutant libraries, which were thereafter screened for Aza activity. Mutants with elevated Aza activity were identified, DNA sequenced, and the proteins purified. The two most active mutants showed up to 70-fold higher catalytic efficiency than the parental GST A2-2. The structure of the most active triple mutant (L107G/L108D/F222H) enzyme was determined by X-ray crystallography demonstrating significant changes in the topography of the active site facilitating productive binding of Aza as a substrate. © 2012 Elsevier Ltd.

Barbet-Massin E.,University Claude Bernard Lyon 1 | Pell A.J.,University Claude Bernard Lyon 1 | Jaudzems K.,Latvian Institute of Organic Synthesis | Franks W.T.,Leibniz Institute for Molecular Pharmacology | And 8 more authors.
Journal of Biomolecular NMR | Year: 2013

We present here 1H-detected triple-resonance H/N/C experiments that incorporate CO-CA and CA-CB out-and-back scalar-transfer blocks optimized for robust resonance assignment in biosolids under ultra-fast magic-angle spinning (MAS). The first experiment, (H)(CO)CA(CO)NH, yields 1H-detected inter-residue correlations, in which we record the chemical shifts of the CA spins in the first indirect dimension while during the scalar-transfer delays the coherences are present only on the longer-lived CO spins. The second experiment, (H)(CA)CB(CA)NH, correlates the side-chain CB chemical shifts with the NH of the same residue. These high sensitivity experiments are demonstrated on both fully-protonated and 100 %-HN back-protonated perdeuterated microcrystalline samples of Acinetobacter phage 205 (AP205) capsids at 60 kHz MAS. © 2013 Springer Science+Business Media Dordrecht.

Barbet-Massin E.,CNRS Institute of Analytical Sciences | Pell A.J.,CNRS Institute of Analytical Sciences | Retel J.S.,Leibniz Institute for Molecular Pharmacology | Andreas L.B.,CNRS Institute of Analytical Sciences | And 26 more authors.
Journal of the American Chemical Society | Year: 2014

Using a set of six 1H-detected triple-resonance NMR experiments, we establish a method for sequence-specific backbone resonance assignment of magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of 5-30 kDa proteins. The approach relies on perdeuteration, amide 2H/ 1H exchange, high magnetic fields, and high-spinning frequencies (ωr/2π ≥ 60 kHz) and yields high-quality NMR data, enabling the use of automated analysis. The method is validated with five examples of proteins in different condensed states, including two microcrystalline proteins, a sedimented virus capsid, and two membrane-embedded systems. In comparison to contemporary 13C/15N-based methods, this approach facilitates and accelerates the MAS NMR assignment process, shortening the spectral acquisition times and enabling the use of unsupervised state-of-the-art computational data analysis protocols originally developed for solution NMR. © 2014 American Chemical Society.

Jaudzems K.,Latvian Institute of Organic Synthesis | Tars K.,Biomedical Research and Study Center | Maurops G.,Latvian Institute of Organic Synthesis | Ivdra N.,Latvian Institute of Organic Synthesis | And 8 more authors.
ACS Medicinal Chemistry Letters | Year: 2014

Antimalarial hit 1SR (TCMDC-134674) identified in a GlaxoSmithKline cell based screening campaign was evaluated for inhibitory activity against the digestive vacuole plasmepsins (Plm I, II, and IV). It was found to be a potent Plm IV inhibitor with no selectivity over Cathepsin D. A cocrystal structure of 1SR bound to Plm II was solved, providing structural insight for the design of more potent and selective analogues. Structure-guided optimization led to the identification of structurally simplified analogues 17 and 18 as low nanomolar inhibitors of both, plasmepsin Plm IV activity and P. falciparum growth in erythrocytes. © 2014 American Chemical Society.

Leitans J.,Biomedical Research and Study Center | Sprudza A.,Latvian Institute of Organic Synthesis | Tanc M.,University of Florence | Vozny I.,Latvian Institute of Organic Synthesis | And 3 more authors.
Bioorganic and Medicinal Chemistry | Year: 2013

We report here a series of 2-thiophene-sulfonamides incorporating 1-substituted aryl-1,2,3-triazolyl moieties, prepared by click chemistry from 5-ethynylthiophene-2-sulfonamide and substituted aryl azides. The new sulfonamides were investigated as inhibitors of the zinc metalloenzyme CA (EC, and more specifically against the human (h) cytosolic isoforms hCA I and II and the transmembrane, tumor-associated ones hCA IX and XII: The new compounds were medium-weak hCA I inhibitors (KIs in the range of 224-7544 nM), but were compactly, highly effective, low nanomolar hCA II inhibitors (KIs of 2.2-7.7 nM). The tumor-associated hCA IX was inhibited with KIs ranging between 5.4 and 811 nM, whereas hCA XII with inhibition constants in the range of 3.4-239 nM. The X-ray crystal structure of the adducts of two such compounds bound to hCA II (one incorporating 1-naphthyl, the other one 3-cyanophenyl moieties) evidenced the reasons of the high affinity for hCA II. Highly favorable, predominantly hydrophobic interactions between the sulfonamide scaffold and the hCA II active site were responsible for the binding, in addition to the coordination of the sulfamoyl moiety to the zinc ion. The tails of the two inhibitors adopted very diverse orientations when bound to the active site, with the naphthyltriazolyl moiety orientated towards the hydrophobic half of the active site, and the 3-cyanophenyl one pointing towards the hydrophilic half. These data may be used for the structure-based drug design of even more effective hCA II inhibitors, with potential use as antiglaucoma agents or as diuretics. © 2013 Elsevier Ltd. All rights reserved.

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