Synthesis and reactivity of trigonal copper(I) compounds, crystal structure of bis(tetrahydropyrimidine-2-thione)copper(I) bromide

Reaction of monovalent copper halides with excess tetrahydropyrimidine-2-thione (thpmtH(2)) in acetonitrile results in the formation of three-coordinate monomer products of formula Cu(thpmtH(2))(2)X. The crystal and molecular structure of the bromo complex is reported and discussed with respect to analogous copper(I) complexes. The compound crystallizes in the tetragonal system, space group, P4(1)2(1)2 with a = 8.005(1), c = 21.3 1(1) Angstrom, and Z = 4. The two Cu-S bonds are 2.215(4) A and the Cu-Br bond distance is 2.405(2) Angstrom, the interbond angles around copper being exactly 360 degrees. Reactivity of the title compound as well as of its iodo counterpart towards Lewis bases was also investigated; the two compounds react readily, in stoicheiometric amounts, with tertiary phosphine and arsine ligands forming monomeric four-coordinate Cu(I) species, the structures of which were deduced by spectroscopic measurements

Structural and spectroscopic characterization of copper(I) halogen complexes with omega-thiocaprolactam and triphenylphosphine

A series of mixed ligand copper(I) halogeno complexes with omega-thiocaprolactam, (tclH) and triphenylphosphine (PPh(3)) of general formula Cu(tclH)(n)(PPh(3))(3-n)X where n = 1, 2 and X = CI, Pr, I has been studied. The crystal structure of Cu(tclH)(PPH3)(2)Br is reported and discussed with respect to those of other members of the series. Solution C-13 and P-31 NMR spectra of the compounds are related to structural characteristics. Cu(tclH)(PPH3)(2)Br crystallizes in the monoclinic system, space group P2(1)/c, with a = 16.11(2), b = 9.749(2), c = 26.46(3)Angstrom, beta = 91.03(5)degrees and Z = 4. The local copper environment is irregular tetrahedral with Cu-P equal to 2.289(4) and 2.277(4)Angstrom, while Cu-S and Cu-Br are 2.344(4) and 2.522(2)Angstrom, respectively

New links between protein biosynthesis and nonribosomal peptide synthesis

Hybrid glass–carbon 2D braided composites with varying carbon contents are impacted using a gas gun by impactors of masses 12.5 and 44.5 g, at impact energies up to 50 J. The damage area detected by ultrasound C-scan is found to increase roughly linearly with impact energy, and is larger for the lighter impactor at the same impact energy. The area of whitening of the glass tows on the distal side corresponds with the measured C-scan damage area. X-ray imaging shows more intense damage, at the same impact energy, for a higher-mass impactor. Braids with more glass content have a modest increase in density, decrease in modulus, and reduction in the C-scan area and dent depth at the impact site, particularly at the higher impact energies. Impact damage is found to reduce significantly the compressive strength, giving up to a 26% reduction at the maximum impact energ

Disruption of Macrodomain Protein SCO6735 Increases Antibiotic Production in Streptomyces coelicolor

ADP-ribosylation is a post-translational modification that can alter the physical and chemical properties of target proteins and that controls many important cellular processes. Macrodomains are evolutionarily conserved structural domains that bind ADP-ribose derivatives and are found in proteins with diverse cellular functions. Some proteins from the macrodomain family can hydrolyze ADP-ribosylated substrates and therefore reverse this post-translational modification. Bacteria and Streptomyces, in particular, are known to utilize protein ADP-ribosylation, yet very little is known about their enzymes that synthesize and remove this modification. We have determined the crystal structure and characterized, both biochemically and functionally, the macrodomain protein SCO6735 from Streptomyces coelicolor This protein is a member of an uncharacterized subfamily of macrodomain proteins. Its crystal structure revealed a highly conserved macrodomain fold. We showed that SCO6735 possesses the ability to hydrolyze PARP-dependent protein ADP-ribosylation. Furthermore, we showed that expression of this protein is induced upon DNA damage and that deletion of this protein in S. coelicolor increases antibiotic production. Our results provide the first insights into the molecular basis of its action and impact on Streptomyces metabolism