Potassium (K +) is an important macronutrient and the most abundant cation in higher plants which plays a key role in various cellular processes. Its accumulation from soil and its distribution throughout diverse plant tissues is mediated by transporter proteins. In plants, different transport systems are known to be involved in the uptake and release of K + from the cells. Though most of the information about the putative K + transporters and their phylogenetic relationships is available in Arabidopsis, it is not the best model for plants with agronomic applications. Recent completion of rice genome sequencing project offered the opportunity to make an inventory of all putative K + transporter proteins. More than 5% of the rice genome appears to encode membrane transport proteins. Unfortunately, several hundreds of putative transporter proteins have not yet been assigned to any families or subfamilies or functions. Therefore, phylogenetic relationships of many K + transporters in rice are analyzed since rice is considered as a model plant because of its high degree of co-linearity with other cereals. Phylogenetic analysis of all K + transporters in rice revealed that they fall into five major branches. Phylogenetic trees of each family define the evolutionary relationships of the members to each other. In each family, closely related isoforms and separate subfamilies existed, indicating possible redundancies and specialized functions. The HAK family is represented by 26 genes and formed the tightest and most distinct branch in the phylogenetic tree. Around 14 genes with conserved P-loop were found in K + channel family out of which 11 genes belong to 1P/6TM (Shaker-type), and three genes to the 2P/4TM (ORK-type). On searching rice genome, it was found that nine genes belonged to Trk family. In rice, K + /H + antiporter family is represented by a single gene. Comparative analysis of rice K + channels with that of Arabidopsis, wheat and maize revealed that while cereals are closely related, Arabidopsis appeared quite distant from rice.

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Diabetes is a metabolic disorder that has emerged recently as a major cause of global concern. Regulation of the blood glucose concentration is essential to maintain the homeostasis. GLUT2, a carrier protein, plays an important role in transporting sugar molecules across the membrane. To understand the function of this carrier molecule, knowledge of its three-dimensional structure is of paramount importance. Homology modeling approach was adopted to decipher the threedimensional structure and features of human GLUT2. Ninety-eight percent residues of the modeled structure lie in the allowed region of the Ramachandran plot and a RMSD of 0.86 Å with the template molecule confirms the reliability of the modeled structure. Comparative transmembrane helix prediction from primary sequence as well as analysis of model revealed presence of 12 helices, which is in agreement with the available literature. Molecular mechanical calculations and docking analysis were performed for the selected 33 compounds. Results showed Glipizide as the best interacting ligand based on the fitness values scored from the binding affinity and minimized energy of the docked complex. These results will aid in efficient designing of inhibitor molecules to curb diabetes.

The enzyme aldoreductase which plays an important role in pathogenesis of diabetic retinopathy, neuropathy, and nephropathy was purified from bovine lens, and its inhibitory activity was studied with the synthesized flavone derivatives 1-(2-hydroxyphenyl)ethanone as the starting material. Experimental study revealed that 2-chloroflavone shows less inhibitory activity of 60-70% than other flavones used in the study. To validate experimental results computationally, docking studies of new flavone derivatives synthesized were performed with the enzyme aldose reductase, and the results indicate that 3-iodo, 4-methyl, 5-chloroflavone and 2-chloroflavone bind with higher and lesser affinities.Docking studies with site directed mutagenesis of Val47Ile, Tyr48His, Pro121Phe, Trp219Tyr, Cys298Ala, Leu300Pro, Ser302Arg, and Cys303Asp of the enzyme altered the inhibition activity of aldose reductase. The regression value (R 2 ) of 0.81 between the docking scores of the known inhibitors and the experimental logIC 50 indicates the reliability of the docking studies. Biological activity and carcinogenic properties predict that 3-iodo, 4-methyl, 5-chloroflavone is the best flavone inhibitor against aldose reductase.

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