Preliminary X-ray crystal structure and partial cDNA-sequence of ascorbate oxidase from zucchini.
Explore the source record for details and available documents.
Amino Acid Sequence↗
Biomedical subjects
A Messerschmidt
Publications and source records attributed to A Messerschmidt.
Crystallization, crystal structure analysis and preliminary molecular model of the bilin binding protein from the insect Pieris brassicae.
The bilin binding protein of the butterfly Pieris brassicae has been prepared, crystallized and its crystal structure determined at high resolution using film and FAST area detector intensity data. The crystallographic asymmetric unit contains a tetramer of identical subunits with a molecular weight of about 90,000. The crystal structure was determined by isomorphous replacement. Use was made of the molecular symmetry to improve phases. A molecular interpretation of the electron density distribution and partial tracing of the polypeptide chain was possible without amino acid sequence information, as the fold is very similar to retinol binding protein. It is characterized by a beta-barrel formed by two orthogonal beta-sheets and an alpha-helix. The bilin pigment seems to be bound within the beta-barrel analogously to retinol in retinol binding protein. The tetramer in the crystal has C2 symmetry and is a dimer of dimers of quasi-equivalent subunits.
Amino Acid Sequence↗
The suitability of Ta6Br12(2+) for phasing in protein crystallography.
The title compound Ta6Br12(2+) is of interest for the analysis of biological structures as a heavy metal derivative with great potential for the structure determination of large protein systems. In macromolecular crystallography the phases of the measured structure factor amplitudes have to be determined by compounds that produce measurable changes of the diffraction intensities. Ta6Br12(2+) uniquely meets the demands of a heavy metal derivative and is an important tool for phase determination, especially considering the structure determination of large protein systems.
Bromides↗
Implications for the catalytic mechanism of the vanadium-containing enzyme chloroperoxidase from the fungus Curvularia inaequalis by X-ray structures of the native and peroxide form.
Implications for the catalytic mechanism of the vanadium-containing chloroperoxidase from the fungus Curvularia inaequalis have been obtained from the crystal structures of the native and peroxide forms of the enzyme. The X-ray structures have been solved by difference Fourier techniques using the atomic model of the azide chloroperoxidase complex. The 2.03 A crystal structure (R = 19.7%) of the native enzyme reveals the geometry of the intact catalytic vanadium center. The vanadium is coordinated by four non-protein oxygen atoms and one nitrogen (NE2) atom from histidine 496 in a trigonal bipyramidal fashion. Three oxygens are in the equatorial plane and the fourth oxygen and the nitrogen are at the apexes of the bipyramid. In the 2.24 A crystal structure (R = 17.7%) of the peroxide derivate the peroxide is bound to the vanadium in an eta2-fashion after the release of the apical oxygen ligand. The vanadium is coordinated also by 4 non-protein oxygen atoms and one nitrogen (NE2) from histidine 496. The coordination geometry around the vanadium is that of a distorted tetragonal pyramid with the two peroxide oxygens, one oxygen and the nitrogen in the basal plane and one oxygen in the apical position. A mechanism for the catalytic cycle has been proposed based on these X-ray structures and kinetic data.
Binding Sites↗
Mode of action of cystathionine beta-lyase.
Cystathionine beta-lyase (CBL) is a member of the gamma-family of pyridoxal-5'-phosphate (PLP)-dependent enzymes (Alexander et al., 1994) that cleave C(beta,gamma)-S bonds of a broad variety of substrates. Recently, we reported the X-ray crystal structures of CBL and the CBL-trifluoroalanine inactivation complex at 1.83 A and 2.3 A resolution, respectively. The structures explicitly reveal the cofactor and substrate binding pockets. Spectral analysis of substrate turnover indicates a change of hydrophobicity in the microenvironment of the aldimine bond. In combination with further spectroscopic data, crystallographic evidence permits the formulation of a likely reaction mechanism.
Chemical Phenomena↗