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One of the most active areas within the field of bioorganometallic chemistry, complexes of N-heterocyclic carbenes (NHCs), have recently gained interest. Herein, we report two luminescent palladium N-heterocyclic carbene complexes; namely [Pd {(C,N)-C 6 H 4 CH 2 NH(CH 2 CH 3 )}(1)] (2) and [Pd{(C,N)-C 6 H 4 CH 2 NH 2 }(1)] (3) (1 = 1-methyl-3-(2-oxo-2-(pyren-1-yl)ethyl)-2,3-dihydroimidazol-2-ylidene) which were synthesized from the reaction of luminescent imidazolium salt (1(H)Br) and binuclear Palladacycles. The interactions of them with CT-DNA evaluated via absorption, emission and CD spectral techniques as well as measurements of viscosity and thermal denaturation and the results have been shown that they bounded to CT-DNA by intercalation and groove binding modes. The in vitro cytotox-icity of compounds 2-3 and 1(H)Br on human breast (MCF-7) and cervical epithelial carcinoma (HeLa) cancer cells lines, indicated the wide range of anticancer activities of them with low IC 50 values. Moreover, based on the protein binding ability studies, the intrinsic fluorescence of BSA could be strongly quenched by compounds via a static quenching mechanism. Competitive binding study using Eosin, Digoxin and Ibuprofen as site markers, indicated that the compounds could bind to sites I and II on BSA structure. Finally, all data obtained from biophysical studies were validated by molecular modeling study. Computational results showed that palladium complexes have the potential for detection of mismatch DNA.

Background: The replacement of carbohydrate sweeteners with protein sweeteners from plants has attracted the interest of researchers because these proteins don’t trigger the insulin response and are more nutritive for consumption in food. Brazzein (Braz) is a small and heatstable sweet protein that has been originally derived from African plant Pentadiplandra brazzeana. In the present work the solubility, sweetness and yield of recombinant forms of Braz in two expression hosts, E. coli and S. cerevisiae were comprised. Methods: The codon-optimized gene of Braz was cloned in expression vectors pET28a and pET41a and GPD. The resulted vectors pET28a-Braz and pET41a-Braz were transformed to BrazS. cerevisiae and the vector GPD-Braz was transformd to S. cerevisiae. The expression of Braz in different systems was analyzed by SDS-PAGE and western blotting. Results: The results verified the heterologous expression of Braz in S. cerevisiae carrying GPD-Braz. Also the expression of Braz as carboxy-terminal extensions of His-tag and glutathione-S-transferase (GST) were verified in transgenic E. coli containing pET28a-Braz and pET41a-Braz, respectively. Conclusion: Although the yield of GST-Braz was higher than His-Braz and Braz expressed in S. cerevisiae, but the higher solubility, sweetness, safety (GRAS) are important advantages of the use of S. cerevisiae as expression host for production of Braz. Therefore the result of present work opens new insights for providing the new sweet yeasts that can be used as food additives.

BACKGROUND Hexavalent chromium Cr(VI) is a toxic and carcinogenic heavy metal. It is highly water soluble and one of the most widely used metals in industry, resulting in soil and water contamination. Nowadays engineering microbes provide new strategies for remediation of heavy metals. RESULTS In the present work, a gene encoding E. coli chromate reductase (YieF) was cloned in pCDF‐1b and was transferred to both cells containing empty pET41a (control strain), and cells containing pET41a‐OsMT1 (R‐MT1) resulted in production of new strains R‐YieF and R‐YieF/MT1, respectively. Both proteins – YieF as His‐tag fusion protein and OsMT1 as glutathione‐S‐transferase fusion protein – appeared in the soluble fraction of R‐YieF/MT1 after induction with isopropyl‐d‐1‐thiogalactopyranoside . The strain R‐YieF/OsMT1 showed high tolerance to Cr6+ and accumulated significantly higher Cr6+ than R‐MT1 (5 mg L−1), R‐YieF (7 mg L−1) and control (2 mg L−1). The accumulation of Cr6+ was dependent on the initial concentration of Cr6+ in the medium, time and the presence of other toxic metals such as Ag+1, Hg+2 and Cd2+. CONCLUSION This study demonstrated that the co‐expression of YieF and OsMT1 could effectively enhance the accumulation of Cr(VI) by E. coli cells and opens new insights into bioremediation strategies. © 2020 Society of Chemical Industry