Histone deacetylases (HDACs) are key enzymes in epigenetics and important drug targets in cancer biology. Whilst it has been established that HDACs regulate many cellular processes, far less is known about the regulation of these enzymes themselves. Here, we show that HDAC8 is allosterically regulated by shifts in populations between exchanging states. An inactive state is identified, which is stabilised by a range of mutations and resembles a sparsely-populated state in equilibrium with active HDAC8. Computational models show that the inactive and active states differ by small changes in a regulatory region that extends up to 28 Å from the active site. The regulatory allosteric region identified here in HDAC8 corresponds to regions in other class I HDACs known to bind regulators, thus suggesting a general mechanism. The presented results pave the way for the development of allosteric HDAC inhibitors and regulators to improve the therapy for several disease states.
The Structural Genomics of Pathogenic Protozoa (SGPP) Consortium aimed to determine crystal structures of proteins from trypanosomatid and malaria parasites in a high throughput manner. The pipeline of target selection, protein production, crystallization, and structure determination, is sketched. Special emphasis is given to a number of technology developments including domain prediction, the use of "co-crystallants," and capillary crystallization. "Fragment cocktail crystallography" for medical structural genomics is also described.
A convenient and simple method for the synthesis of 1-methoxy-5,10-dioxo-5,10-dihydro-1H-benzo[g]isochromene-3-carboxylic acid (3-(dimethylamino)propyl)amide 4c was developed. The key step involves the easy formation of 1,3-disubstituted cyclic alkenyl ether, an important framework of isochromene natural products, with a dual role Pd(II) catalyst.
The globular protein ubiquitin interacts with graphene oxide and undergoes dynamic and reversible association–dissociation as revealed by NMR spectroscopy.
Structural characterization of proteins by NMR spectroscopy begins with the process of sequence specific resonance assignments in which the (1)H, (13)C and (15)N chemical shifts of all backbone and side-chain nuclei in the polypeptide are assigned. This process requires different isotope labeled forms of the protein together with specific experiments for establishing the sequential connectivity between the neighboring amino acid residues. In the case of spectral overlap, it is useful to identify spin systems corresponding to the different amino acid types selectively. With isotope labeling this can be achieved in two ways: (i) amino acid selective labeling or (ii) amino acid selective 'unlabeling'. This chapter describes both these methods with more emphasis on selective unlabeling describing the various practical aspects. The recent developments involving combinatorial selective labeling and unlabeling are also discussed.
Analytical formulation and solution of stress analysis of composite plate subjected to thermo mechanical loading for various ply orientation and thickness of lamina are studied. The main aim of the paper is to investigate how mechanical and thermo mechanical loading would affect the stress ratio and stress distribution of composite plate. The plate is composed of layers of glass-epoxy composite and the orientation of the layers is assumed to be antisymmetric about the neutral axis of the laminate. The plate is subjected to a combined mechanical loading of tensile force and moment along x direction. The thermo mechanical stress is calculated for different ply orientation and thickness ratio, subjected to a temperature change and mechanical loading. The effect of number of lamina and varying thickness of laminate on the stress ratio and stress distribution is studied. The results in this paper are obtained by use of MATLAB Programming and by Finite element software ANSYS 14. Results obtained from both the methods are compared. Such type of loading finds wide application in aircraft flying at high altitude, marine application, medical devices etc.
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