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Reductive Methylation (reductive + methylation)
Selected AbstractsReductive methylation to improve crystallization of the putative oxidoreductase Rv0765c from Mycobacterium tuberculosisACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2007Wilko Rauert Rv0765c from Mycobacterium tuberculosis was cloned and heterologously expressed in Escherichia coli. It was purified using affinity and size-exclusion chromatographic techniques and crystallized. The native protein crystallized in a hexagonal crystal form which diffracted to 7,Å resolution. In an attempt to improve the quality of the Rv0765c crystals, the protein was modified by reductive methylation using dimethylaminoborane and formaldehyde. The modified protein crystallized under different conditions in a tetragonal crystal form, from which diffraction data could be collected to a resolution of 3.2,Å. In both crystal forms of Rv0765c, the asymmetric unit contained two copies of the protein molecule. [source] Synthesis of 2,6-diamino-5-[(2-substituted phenylamino)ethyl]pyrimidin-4(3h)-one as inhibitors of folate metabolizing enzymes,,JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2006Aleem Gangjee A series of eleven novel 2,6-diamino-5-[(2-substituted phenylamino)ethyl]pyrimidin-4(3H)-one derivatives were synthesized as potential inhibitors of dihydrofolate reductase (DHFR) and thymidylate synthase (TS). The synthesis of analogues 2a-f, 3a and 3e was achieved via an improved method. Commercially available anilines 12a-f were used as starting materials which on reaction with chloroacetaldehyde followed by cyanoacetate and cyclocondensation with guanidine afforded 2,6-diamino-5-[(2-substituted phenylamino)ethyl]pyrimidin-4(3H)-one 2a-f in three steps. The N-methyl analogues 3a-3e were prepared by reductive methylation. These compounds were evaluated against dihydrofolate reductase from Escherichia coli, Toxoplasma gondii, Pneumocystis carinii, human, and rat liver. Few compounds were marginally active against dihydrofolate reductase. The most potent inhibitor, (2c) which has a 1-naphthyl substituent on the side chain, has an IC50 = 150 ,M and 9.1 ,M against Escherichia coli and Toxoplasma gondii DHFR, respectively. [source] Structure of the Escherichia coli RNA polymerase , subunit C-terminal domainACTA CRYSTALLOGRAPHICA SECTION D, Issue 7 2010Samuel Lara-González The , subunit C-terminal domain (,CTD) of RNA polymerase (RNAP) is a key element in transcription activation in Escherichia coli, possessing determinants responsible for the interaction of RNAP with DNA and with transcription factors. Here, the crystal structure of E. coli,CTD (, subunit residues 245,329) determined to 2.0,Å resolution is reported. Crystals were obtained after reductive methylation of the recombinantly expressed domain. The crystals belonged to space group P21 and possessed both pseudo-translational symmetry and pseudo-merohedral twinning. The refined coordinate model (R factor = 0.193, Rfree = 0.236) has improved geometry compared with prior lower resolution determinations of the ,CTD structure [Jeon et al. (1995), Science, 270, 1495,1497; Benoff et al. (2002), Science, 297, 1562,1566]. An extensive dimerization interface formed primarily by N- and C-terminal residues is also observed. The new coordinates will facilitate the improved modeling of ,CTD-containing multi-component complexes visualized at lower resolution using X-ray crystallography and electron-microscopy reconstruction. [source] Structures of an alanine racemase from Bacillus anthracis (BA0252) in the presence and absence of (R)-1-aminoethylphosphonic acid (l -Ala-P)ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2008Kinfai Au Bacillus anthracis, the causative agent of anthrax, has been targeted by the Oxford Protein Production Facility to validate high-throughput protocols within the Structural Proteomics in Europe project. As part of this work, the structures of an alanine racemase (BA0252) in the presence and absence of the inhibitor (R)-1-aminoethylphosphonic acid (l -Ala-P) have determined by X-ray crystallography to resolutions of 2.1 and 1.47,Å, respectively. Difficulties in crystallizing this protein were overcome by the use of reductive methylation. Alanine racemase has attracted much interest as a possible target for anti-anthrax drugs: not only is d -alanine a vital component of the bacterial cell wall, but recent studies also indicate that alanine racemase, which is accessible in the exosporium, plays a key role in inhibition of germination in B. anthracis. These structures confirm the binding mode of l -Ala-P but suggest an unexpected mechanism of inhibition of alanine racemase by this compound and could provide a basis for the design of improved alanine racemase inhibitors with potential as anti-anthrax therapies. [source] Reductive methylation to improve crystallization of the putative oxidoreductase Rv0765c from Mycobacterium tuberculosisACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2007Wilko Rauert Rv0765c from Mycobacterium tuberculosis was cloned and heterologously expressed in Escherichia coli. It was purified using affinity and size-exclusion chromatographic techniques and crystallized. The native protein crystallized in a hexagonal crystal form which diffracted to 7,Å resolution. In an attempt to improve the quality of the Rv0765c crystals, the protein was modified by reductive methylation using dimethylaminoborane and formaldehyde. The modified protein crystallized under different conditions in a tetragonal crystal form, from which diffraction data could be collected to a resolution of 3.2,Å. In both crystal forms of Rv0765c, the asymmetric unit contained two copies of the protein molecule. [source] | ||||||||||