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Cytogenet Genome Res,
2013]
Down syndrome (DS) is caused by an extra copy of all or part of the long arm of human chromosome 21 (HSA21). While the complete phenotype is both complex, involving most organs and organ systems, and variable in severity among individuals, intellectual disability (ID) is seen in all people with DS and may have the most significant impact on quality of life. Because the worldwide incidence of DS remains at approximately 1 in 1,000 live births, DS is the most common genetic cause of ID. In recent years, there have been important advances in our understanding of the functions of genes encoded by HSA21 and in the number and utility of in vitro and in vivo systems for modeling DS. Of particular importance, several pharmacological treatments have been shown to rescue learning and memory deficits in one mouse model of DS, the Ts65Dn. Because adult mice were used in the majority of these experiments, there is considerable interest in extending the studies to human clinical trials, and a number of trials have been completed, are in progress or are being planned. A recent conference brought together researchers with a diverse array of expertise and interests to discuss (1) the functions of HSA21 genes with relevance to ID in DS, (2) the utility of model systems including Caenorhabditis elegans, zebrafish and mouse, as well as human neural stem cells and induced pluripotent stems cells, for studies relevant to ID in DS, (3) outcome measures used in pharmacological treatment of mouse models of DS and (4) outcome measures suitable for clinical trials for cognition in adults and children with DS.
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Int J Biol Macromol,
2016]
Brugia malayi Glucose 6-phosphate dehydrogenase apoenzyme (BmG6PD) was expressed and purified by affinity chromatography to study the differences in kinetic properties of enzyme and the effect of the cofactor NADP(+) binding on enzyme stability. The presence of cofactor NADP(+) influenced the tertiary structure of enzyme due to significant differences in the tryptophan microenvironment. However, NADP(+) binding have no effect on secondary structure of the enzyme. Quenching with acrylamide indicated that two or more tryptophan residues became accessible upon cofactor binding. Unfolding and cross linking study of BmG6PD showed that NADP(+) stabilized the protein in presence of high concentration of urea/GdmCl. A homology model of BmG6PD constructed using human G6PD (PDB id: 2BH9) as a template indicated 34% -helix, 19% -sheet and 47% random coil conformations in the predicted model of the enzyme. In the predicted model binding of NADP(+) to BmG6PD was less tight with the structural sites (-10.96 KJ/Mol binding score) as compared with the coenzyme site (-15.47 KJ/Mol binding score).
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J Enzyme Inhib Med Chem,
2013]
The aspartic protease inhibitory efficiency of rBm-33, an aspin from a filarial parasite Brugia malayi was investigated. rBm-33 was found to be thermostable up to 90C and it forms a stable 'enzyme-product' complex with human pepsin. Aspartic protease inhibitory activity was investigated using UV spectroscopy and isothermal titration calorimetry. Our results suggest that rBm-33 inhibits the activity of important human aspartic proteases that were examined with binding constants (Kb) values between 10.23 x 10(3) and 6.52 x 10(3) M(-1). The binding reactions were enthalpy driven with Hb values between -50.99 and -46.07 kJ mol(-1). From kinetic studies, pepsin inhibition by rBm-33 was found to be linear competitive with an inhibition constant (Ki) of 2.5 (+/-0.8) nM. Because of the inhibitory efficacy of Bm-33 against important human aspartic proteases which play a vital role in immune-regulation along with other functions, Bm-33 can be projected as a drug target for the filariasis.