Maria Przybylska

1.70 A resolution structure of myoglobin from yellowfin tuna. An example of a myoglobin lacking the D helix.

The crystal structure of metmyoglobin from yellowfin tuna (Thunnus albacares) has been determined by molecular replacement methods and refined to a conventional R factor of 0.177 for all observed reflections in the range of 6.0-1.70 A resolution. Like other myoglobins for which a high-resolution structure is available, the polypeptide chain is organized into several helices that cooperate to form a hydrophobic pocket into which the heme prosthetic group is non-covalently bound; however, the D helix observed in other myoglobins is absent in myoglobin from yellowfin tuna and has been replaced with a random coil. As well, the A helix has a pronounced kink due to the presence of Pro16. The differences in structure between this and sperm whale myoglobin can be correlated with their reported dioxygen affinity and dissociation. The structure is in agreement with reported fluorescence data which show an increased Trp14.heme distance in yellowfin tuna compared to sperm whale myoglobin.

Preliminary crystal structure analysis of an Fab specific for a Salmonella O-polysaccharide antigen.

The Fab from an IgG1, lambda murine monoclonal antibody with specificity for the O-polysaccharide antigen of Salmonella typhimurium has been crystallized in the absence and presence of hapten. The conditions for crystal growth were vapor diffusion equilibration with 16 to 23% polyethylene glycol 8000 solutions. Data have been collected from crystals of the complex in space group P212121, a = 60.6 A, b = 111.3 A, c = 61.1 A, and refinement of a molecular replacement solution is underway.

5β-hydroxygitoxigenin, a product of gitoxigenin produced by Daucus carota culture

Abstract The product of gitoxigenin transformation by Daucus carota Ca68 cell suspension culture has been isolated from culture filtrates and identified as 5β-hydroxygitoxigenin. A summary of the physico-chemical data for this novel compound is reported for the first time.

Crystallization of the haptoglobin–hemoglobin complex

Two orthorhombic forms of crystals of the haptoglobin-hemoglobin complex were obtained using polyethylene glycol as precipitant. These crystals did not diffract well enough for data collection and work on the complex is no longer continued. However, the description of the crystallization conditions may be useful in future endeavors to obtain suitable crystals.

X-ray Powder Diffraction Data for 2,4-Dinitrophenylhydrazones of Aldehydes and Ketones

In order to extend the data available for the identification of carbonyl compounds, the x-ray powder diffraction patterns of sixty-four 2,4-dinitrophenylhydrazones of aldehydes and ketones were determined. An alphabetical table includes 39 additional compounds found in the literature. A second numerical table indexes the spacing and intensities of the three strongest lines in Hanawalt groups. The complete new diffraction pattern data are available from the American Documentation Institute.

Crystallization and preliminary crystallographic data for oncomodulin

Abstract Oncomodulin, a parvalbumin-like calcium-binding protein isolated from rat tumours, has been crystallized from 33% polyethylene glycol 6000 at pH 5·2 in the presence of CaCl2 and dithiothreitol. The crystals belong to the space group P212121, with unit cell dimensions a = 39·59(1) A , b = 64·28(2) A and c = 33·07(1) A , and have one molecule of oncomodulin per asymmetric unit. Their solvent content is only 31% ( v v ) and they are remarkably stable. Three complete sets of data, one to 1·85 A resolution for the native protein and one to 2·0 A for each of two heavy-atom derivatives, have been collected. A three-dimensional structure analysis is in progress.