L. donovani XPRT: Molecular characterization and evaluation of inhibitors.

Among all PRT enzymes of purine salvage pathway in Leishmania, XPRT (Xanthine phosphoribosyl transferase) is unique in its substrate specificity and their non-existence in human. It is an interesting protein not only for drug designing but also to understand the molecular determinants of its substrate specificity. Analysis of the 3D model of L. donovani XPRT (Ld-XPRT) revealed that Ile 209, Glu 215 and Tyr 208 may be responsible for the altered substrate specificity of Ld-XPRT. Comparisons with it's nearest homologue in humans, revealed significant differences between the two. A 28 residue long unique motif was identified in Ld-XPRT, which showed highest fluctuation upon substrate binding during MD simulations. In kinetic analysis, Ld-XPRT could phosphoribosylate xanthine, hypoxanthine and guanine with Km values of 7.27, 8.13, 8.48µM and kcat values of 2.24, 1.82, 1.19min-1 respectively. Out of 159 compounds from docking studies, six compounds were characterized further by fluorescence spectroscopy, CD spectroscopy and enzyme inhibition studies. Fluorescence quenching experiment was performed to study the binding of inhibitors with Ld-XPRT and dissociation constants were calculated. Four compounds are bi-substrate analogues and show competitive inhibition with both the substrates (Xanthine and PRPP) of Ld-XPRT. The CD spectral analysis revealed that the binding of inhibitors to Ld-XPRT induce change in its tertiary structure, where as its secondary structure pattern remains unchanged. Two Ld-XPRT inhibitors (dGDP and cGMP), which also have ability to inhibit Leishmanial HGPRT, are predicted as potential drug candidates as it can inhibit both the important enzymes of the purine salvage pathway.

In Silico Analysis for Five Major Cereal Crops Phytocystatins.

Five major cereal crops such as rice, wheat, maize, barley and sorghum are continuously threatened by a multitude of pathogens and other disorders. Cystatins offers a pivotal role in deciding the promising plant response. The use of bioinformatics tools for phylogenetic relationships of five major cereal crop (rice, wheat, maize, barley and sorghum) phytocystatins based on amino acid sequence information was elucidated, and their secondary and tertiary structures were investigated for structural comparisons. Twenty-eight distinct phytocystatins from 28 plant species were investigated. Phytocystatins could be divided into five distinct phylogenetic groups. Five major cereal crops their structural features were highly conserved, and their amino acid sequence similarities ranged from 48 to 86 %. A new highly conserved amino acid sequence motif, YEAKxWxKxF, in the C-terminal end being unique to phytocystatins was identified. The predicted 3D homology models showed a high conservation of the general central structure of the phytocystatins, i.e., the 4-5 anti-parallel [Formula: see text]-sheets, wrapping halfway round a single central [Formula: see text]-helix and particularly the three active site regions, the N-terminal, the first and second hairpin loops. Any structural differences seem to be mainly in the length of the N- and C-terminal, the length of the second hairpin loop and the fifth [Formula: see text]-sheet. Via docking experiments, small heterogeneities were observed in the vicinity of the OC-I active sites that seemed to be influential in the binding process and stability of the resultant inhibitor-protease complex.

In silico analysis for five major cereal crops phytocystatins.

Five major cereal crops like rice, wheat, maize, barley and sorghum are continuously threatened by a multitude of pathogens and other disorders. Cystatins offers a pivotal role in deciding the promising plant response. The use of bioinformatics tools for phylogenetic relationships of five major cereal crops (rice, wheat, maize, barley and sorghum) phytocystatins based on amino acid sequence information was elucidated and their secondary and tertiary structures were investigated for structural comparisons. Twenty eight distinct phytocystatins from 28 plant species were investigated. Phytocystatins could be divided into five distinct phylogenetic groups. Five major cereal crops their structural features were highly conserved their amino acid sequence similarities ranged from 48 to 86%. A new highly conserved amino acid sequence motif, YEAKxWxKxF, in the C-terminal end being unique to phytocystatins was identified. The predicted 3D homology models showed a high conservation of the general central structure of the phytocystatins i.e. the 4-5 anti-parallel ß-sheets, wrapping halfway round a single central α-helix and particularly the three active site regions, the N-terminal, the 1st and 2nd hairpin loops. Any structural differences seem to be mainly in the length of the N and C terminal, the length of the 2nd hairpin loop and the 5th ß-sheet. Via docking experiments, small heterogeneities were observed in the vicinity of the OC-I active sites that seemed to be influential in the binding process and stability of the resultant inhibitor-protease complex.

FCDD: A Database for Fruit Crops Diseases.

UNLABELLED: Fruit Crops Diseases Database (FCDD) requires a number of biotechnology and bioinformatics tools. The FCDD is a unique bioinformatics resource that compiles information about 162 details on fruit crops diseases, diseases type, its causal organism, images, symptoms and their control. The FCDD contains 171 phytochemicals from 25 fruits, their 2D images and their 20 possible sequences. This information has been manually extracted and manually verified from numerous sources, including other electronic databases, textbooks and scientific journals. FCDD is fully searchable and supports extensive text search. The main focus of the FCDD is on providing possible information of fruit crops diseases, which will help in discovery of potential drugs from one of the common bioresource-fruits. The database was developed using MySQL. The database interface is developed in PHP, HTML and JAVA. FCDD is freely available. AVAILABILITY: http://www.fruitcropsdd.com/