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Oilseeds of the plant family Brassicaceae are important for providing both lipid and protein contents to human nutrition. Cruciferins (12S globulins) are seed storage proteins, which are getting attention due to their allergenic and pathogenicity related nature. This study describes the purification and characterization of a trimeric (∼190 kDa) cruciferin protein from the seeds of Brassica nigra (L.). Cruciferin was first partially purified by ammonium sulfate precipitation (30% saturation constant) and further purified by size exclusion chromatography. The N-terminal amino-acid sequence analysis showed 82% sequence homology with cruciferin from Arabidopsis thaliana. The 50–55 kDa monomeric cruciferin produced multiple bands of two major molecular weight ranges (α-polypeptides of 28–32 kDa and β-polypeptides of 17–20 kDa) under reduced conditions of SDS-PAGE. The 2D gel electrophoretic analysis showed the further separation of the bands into their isoforms with major pI ranges between 5.7 and 8.0 (α-polypeptides) and 5.5–8.5 (β-polypeptides). The Dynamic Light Scattering (DLS) showed the monodisperse nature of the cruciferin with hydrodynamic radius of 5.8 ± 0.1 nm confirming the trimeric nature of the protein. The Circular Dichroism (CD) spectra showed both α-helices and β-sheets in the native conformation of the trimeric protein. The pure cruciferin protein (40 mg/ml) was successfully crystallized; however, the crystals diffracted only to low resolution data (8 A). Small-angle x-ray scattering (SAXS) was applied to gain insights into the three-dimensional structure in solution. SAXS showed that the radius of gyration is 4.24 ± 0.25 nm and confirmed the nearly globular shape. The SAXS based ab initio dummy model of B. nigra cruciferin was compared with 11S globulins (PDB ID: 3KGL ) of B. napus which further confirmed a highly similar molecular weight and globular shape indicating a conserved trimerization of B. nigra cruciferin. The comparison of the scattering patterns of both proteins showed a minimized χ2-value of 1.337 confirming a similar molecular structure. This is the first report describing the purification and characterization of a cruciferin protein from seeds of B. nigra.

The title compound, [Cu(tmeda)(NCS)2]n (1) (tmeda = N,N,N′,N′-tetramethylethylenediamine) was prepared by the reaction of CuCl2·2H2O with potassium thiocyanate and N,N,N′,N′-tetramethylethylenediamine, and its structure was determined by X-ray crystallography. The crystal structure shows that the complex exists in the form of one dimensional polymer consisting of [Cu(tmeda)(NCS)2] units. Each Cu(II) ion is bound to two nitrogen atoms of tmeda and two nitrogen atoms and one sulfur of thiocyanate ligands adopting a distorted square pyramidal geometry. The different bonds to the metal centre are analyzed using DFT calculations that, additionally, give support to the energetically preferred polymeric structure in comparison to the monomeric or hydrated species. The electrochemical properties of the complex were studied in DMSO. Antimicrobial properties of the complex were evaluated by minimum inhibitory concentration and the results showed that the complex exhibited remarkable activities against gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), molds (Aspergillus niger, Penicillium citrinum) and yeasts (Candida albicans, Saccharomyces cerevisiae).