Oxalyl-coenzyme A decarboxylase is a thiamin diphosphate dependent enzyme active in the catabolism of the highly toxic compound oxalate. The enzyme from Oxalobacter formigenes has been expressed as a recombinant protein in Escherichia coli, purified to homogeneity and crystallized. Two crystal forms were obtained, one showing poor diffraction and the other merohedral twinning. Crystals in the former category belong to the tetragonal space group P4(2)2(1)2. Data to 4.1 A resolution were collected from these crystals and an incomplete low resolution structure was initially determined by molecular replacement. Crystals in the latter category were obtained by co-crystallizing the protein with coenzyme A, thiamin diphosphate and Mg(2+)-ions. Data to 1.73 A were collected from one of these crystals with apparent point group 622. The crystal was found to be heavily twinned, and a twin ratio of 0.43 was estimated consistently by different established methods. The true space group P3(1)21 was deduced, and a molecular replacement solution was obtained using the low resolution structure as template when searching in detwinned data.
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http://dx.doi.org/10.1016/j.bbapap.2005.08.016 | DOI Listing |
Acta Crystallogr E Crystallogr Commun
August 2024
Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany.
The structures of seven gold(III) halide derivatives of general formula Au ( = methyl-pyridines or di-methyl-pyridines, = Cl or Br) are presented: tri-chlorido-(2-methyl-pyridine)-gold(III), [AuCl(CHN)], (as two polymorphs and ); tri-bromido-(2-methyl-pyridine)-gold(III), [AuBr(CHN)], ; tri-bromido-(3-methyl-pyridine)-gold(III), [AuBr(CHN)], ; tri-bromido-(2,4-di-meth-yl-pyridine)-gold(III), [AuBr(CHN)], ; tri-chlorido-(3,5-di-methylpyridine)-gold(III), [AuCl(CHN)], ; tri-bromido-(3,5-di-methyl-pyridine)-gold(III), [AuBr(CHN)], , and tri-chlorido-(2,6-di-methyl-pyridine)-gold(III), [AuCl(CHN)], . Additionally, the structure of , the 1:1 adduct of and , [AuBr(CHN)]·[AuBr(CHN)], is included. All the structures crystallize solvent-free, and all have ' = 1 except for and , which display crystallographic twofold rotation symmetry, and , which has ' = 2.
View Article and Find Full Text PDFActa Crystallogr C Struct Chem
July 2024
School of Natural Sciences & Catalysis Research Center (CRC), Technische Universität München, Ernst-Otto-Fischer Strasse 1, 85748 Garching, Germany.
Geminal and vicinal bis(trifluoromethanesulfonate) esters are highly reactive alkylene synthons used as potent electrophiles in the macrocyclization of imidazoles and the transformation of bypyridines to diquat derivatives via nucleophilic substitution reactions. Herein we report the crystal structures of methylene (CHFOS) and ethylene bis(trifluoromethanesulfonate) (CHFOS), the first examples of a geminal and vicinal bis(trifluoromethanesulfonate) ester characterized by single-crystal X-ray diffraction (SC-XRD). With melting points slightly below ambient temperature, both reported bis(trifluoromethanesulfonate)s are air- and moisture-sensitive oils and were crystallized at 277 K to afford two-component non-merohedrally twinned crystals.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
April 2024
Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany.
The structure of the title compound, CHBrNO, contains two independent mol-ecules connected by hydrogen bonds of the type N-H⋯N≡C to form a dimer. The configuration at the exocyclic C=C double bond is . The mol-ecules are roughly planar except for the isopropyl groups.
View Article and Find Full Text PDFActa Crystallogr D Struct Biol
February 2024
Mitchell Cancer Institute, University of South Alabama Health, 1660 Springhill Avenue, Mobile, AL 36604, USA.
Nanobodies (VHHs) are single-domain antibodies with three antigenic CDR regions and are used in diverse scientific applications. Here, an ∼14 kDa nanobody (A5) specific for the endonuclease VIII (Nei)-like 1 or NEIL1 DNA glycosylase involved in the first step of the base-excision repair pathway was crystallized and its structure was determined to 2.1 Å resolution.
View Article and Find Full Text PDFUnlabelled: Nanobodies or VHHs (Variable Heavy domains of Heavy chain) are single domain antibodies that comprise three antigenic complementary determining regions (CDR). Nanobodies are used in numerous scientific applications including, bio-imaging, diagnosis, therapeutics, and macromolecular crystallography. We obtained crystals of a ∼14 kDa nanobody specific for the NEIL1 DNA glycosylase (hereafter called A5) in 0.
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