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Although recognized in small molecules for quite some time, the implications of halogen bonding in biomolecular systems are only now coming to light. In this study, several systems of proteins in complex with halogenated ligands have been investigated by using a two-layer QM/MM ONIOM methodology. In all cases, the halogen-oxygen distances are shown to be(More)
For proof-of-concept of halogen bonding in drug design, a series of halogenated compounds were designed based on a lead structure as new inhibitors of phosphodiesterase type 5. Bioassay results revealed a good correlation between the measured bioactivity and the calculated halogen bond energy. Our X-ray crystal structures verified the existence of the(More)
AmtB is one of the ammonium transporter proteins facilitating the ammonium transport across the cellular membranes. Experimentally, the substrate used in in vitro studies is the radio labeled [(14)C]methylammonium, rather than ammonium itself. To explore the similarity and difference of the conduction mechanism of methylamine and ammonia molecules through(More)
The hydrogen bond acceptor capability of halogens has long been underappreciated in the field of biology. In this work, we have surveyed structures of protein complexes with halogenated ligands to characterize geometrical preferences of C-X...H contacts and contributions of such interactions to protein-ligand binding affinity. Notably, F...H interactions in(More)
The significance of amination of aryl halides has been manifested by its wide applications in the synthesis of the organically and medicinally interesting building blocks containing the N-aryl moiety throughout pharmaceuticals, agrochemicals, natural products, and materials. The stateof-the-art in the area includes the copper-mediated Ullmann coupling and(More)
Neutral phytase is used as a feed additive for degradation of anti-nutritional phytate in aquatic feed industry. Site-directed mutagenesis of Bacillus amyloliquefaciens DSM 1061 phytase was performed with an aim to increase its activity. Mutation residues were chosen based on multiple sequence alignments and structure analysis of neutral phytsaes from(More)
Castor cake is the residue in castor oil production in which many active components exist and the major one among them is ricinine. In this study, optimization of extraction of ricinine from castor cake using ultrasonic-microwave synergistic extraction (UMSE) was investigated to obtain high yield and purity by Box-Behnken design (BBD) response surface(More)
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