|
| ||
|
|
||
Bond Linking (bond + linking)
Selected AbstractsSingle-step affinity purification of recombinant proteins using a self-excising module from Neisseria meningitidis FrpCPROTEIN SCIENCE, Issue 10 2008Lenka Sadilkova Abstract Purification of recombinant proteins is often a challenging process involving several chromatographic steps that must be optimized for each target protein. Here, we developed a self-excising module allowing single-step affinity chromatography purification of untagged recombinant proteins. It consists of a 250-residue-long self-processing module of the Neisseria meningitidis FrpC protein with a C-terminal affinity tag. The N terminus of the module is fused to the C terminus of a target protein of interest. Upon binding of the fusion protein to an affinity matrix from cell lysate and washing out contaminating proteins, site-specific cleavage of the Asp,Pro bond linking the target protein to the self-excising module is induced by calcium ions. This results in the release of the target protein with only a single aspartic acid residue added at the C terminus, while the self-excising affinity module remains trapped on the affinity matrix. The system was successfully tested with several target proteins, including glutathione-S-transferase, maltose-binding protein, ,-galactosidase, chloramphenicol acetyltransferase, and adenylate cyclase, and two different affinity tags, chitin-binding domain or poly-His. Moreover, it was demonstrated that it can be applied as an alternative to two currently existing systems, based on the self-splicing intein of Saccharomyces cerevisiae and sortase A of Staphylococcus aureus. [source] 3-Nitrophenol,4,4,-bipyridyl N,N,-dioxide (2/1): a DFT study and CSD analysis of DPNO molecular complexesACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2010Rodolfo Moreno-Fuquen The title 2:1 complex of 3-nitrophenol (MNP) and 4,4,-bipyridyl N,N,-dioxide (DPNO), 2C6H5NO3·C10H8N2O2 or 2MNP·DPNO, crystallizes as a centrosymmetric three-component adduct with a dihedral angle of 59.40,(8)° between the planes of the benzene rings of MNP and DPNO (the DPNO moiety lies across a crystallographic inversion centre located at the mid-point of the C,C bond linking its aromatic rings). The complex owes its formation to O,H...O hydrogen bonds [O...O = 2.605,(3),Å]. Molecules are linked by intermolecular C,H...O and C,H...N interactions forming R21(6) and R22(10) rings, and R66(34) and R44(26) macro-rings, all of which are aligned along the [01] direction, and R22(10) and R21(7) rings aligned along the [010] direction. The combination of chains of rings along the [01] and [010] directions generates the three-dimensional structure. A total of 27 systems containing the DNPO molecule and forming molecular complexes of an organic nature were analysed and compared with the structural characteristics of the dioxide reported here. The N,O distance [1.325,(2),Å] depends not only on the interactions involving the O atom at the N,O group, but also on the structural ordering and additional three-dimensional interactions in the crystal structure. A density functional theory (DFT) optimized structure at the B3LYP/6-311G(d,p) level is compared with the molecular structure in the solid state. [source] An oximino tautomer of 1- n -decyl-4-hydroxyimino-3-methyl-1H -pyrazol-5(4H)-oneACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2006Ricardo Baggio The title compound, C14H25N3O2, consists of a five-membered heterocyclic ring to which a pendant decyl group is attached. The oximino tautomeric character of the molecule is clearly defined by the distribution of well defined double bonds in the heterocycle region (one C=O and two C=N). The most conspicuous packing interaction is the strong intermolecular hydrogen bond linking the oximino OH group and the carbonyl O atom to define broad planar hydrophilic strips running along the unique b axis. The alkyl chains adopt a fully extended conformation and lie almost at right angles to these one-dimensional structures, defining their hydrophobic counterpart. [source] Two new polymorphs of diphenyl(4-pyridyl)methyl methacrylateACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2004Gerrit Gobius du Sart The title compound (D4PyMA), C22H19NO2, exhibits polymorphism after crystallization by slow evaporation from a binary mixture of chloroform and hexane. Long needle-like crystals have an orthorhombic structure (space group Fdd2), with one molecule in the asymmetric unit, while small tablet-like crystals exhibit a monoclinic crystal structure (space group P21/n), in which two independent but chemically identical molecules comprise the asymmetric unit. The bond lengths and angles are normal, while the torsion angles around the ,C,O, bond linking the diphenyl(4-pyridyl)methyl and methacrylate groups show the flexibility of the molecule by way of packing effects. The two polymorphs both contain weak C,H,, and C,H,O/N contacts but have different conformations. [source] (1,3-Dimethylimidazolidine-2-selone-,Se)bis(1,10-phenanthroline-,2N,N,)copper(II) bis(perchlorate) and bis(2,2,-bipyridyl-,2N,N,)(imidazolidine-2-thione-,S)copper(II) bis(perchlorate)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2007Alexander J. Blake In the first title salt, [Cu(C12H8N2)2(C5H10N2Se)](ClO4)2, the CuII centre occupies a distorted trigonal,bipyramidal environment defined by four N donors from two 1,10-phenanthroline (phen) ligands and by the Se donor of a 1,3-dimethylimidazolidine-2-selone ligand, with the equatorial plane defined by the Se and by two N donors from different phen ligands and the axial sites occupied by the two remaining N donors, one from each phen ligand. The Cu,N distances span the range 1.980,(10),2.114,(11),Å and the Cu,Se distance is 2.491,(3),Å. Intermolecular ,,, contacts between imidazolidine rings and the central rings of phen ligands generate chains of cations. In the second salt, [Cu(C10H8N2)2(C3H6N2S)](ClO4)2, the CuII centre occupies a similar distorted trigonal,bipyramidal environment comprising four N donors from two 2,2,-bipyridyl (bipy) ligands and an S donor from an imidazolidine-2-thione ligand. The equatorial plane is defined by the S donor and two N donors from different bipy ligands. The Cu,N distances span the range 1.984,(6),2.069,(7),Å and the Cu,S distance is 2.366,(3),Å. Intermolecular ,,, contacts between imidazolidine and pyridyl rings form chains of cations. A major difference between the two structures is due to the presence in the second complex of two N,H...O hydrogen bonds linking the imidazolidine N,H hydrogen-bond donors to perchlorate O-atom acceptors. [source] 2-Bromo-5-hydroxybenzaldehydeACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2000A. Matos Beja The molecules of the title compound, C7H5BrO2, form zigzag chains running along the b axis and are stacked in layers perpendicular to the a axis. Intermolecular bonding occurs through hydrogen bonds linking the hydroxyl and carbonyl groups, with an O,O distance of 2.804,(4),Å. The Br atom deviates significantly from the plane of the ring and the aldehyde group is twisted by 7.1,(5)° around the Csp2,Caryl bond. The geometry of the molecule in the crystal is compared to that given by ab initio quantum mechanical calculations for the isolated molecule, using a molecular orbital Hartree,Fock method and density functional theory. [source] | ||||||||||