02180nas a2200193   4500008004100000022001400041245010100055210006900156260007100225300001400296490000700310520144300317100002101760700002401781700001501805700002401820700001801844856012401862       2015                        eng d  a0020-166900aPyrazine-based organometallic complex: synthesis, characterization, and supramolecular chemistry0 aPyrazinebased organometallic complex synthesis characterization   a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR  a2543-25500 v543 a<p>The design, synthesis, and characterization of a new pyrazine-based ditopic platinum(II) organometallic complex are reported. The molecular structure of the organoplatinum pyrazine dipod was determined by single-crystal X-ray crystallography. The potential utility of this organometallic ditopic acceptor as a building block in the construction of neutral metallasupramolecular macrocycles containing the pyrazine motif was explored. Pyrazine motifs containing supramolecules were characterized by multinuclear NMR (including H-1 DOSY), mass spectrometry, and elemental analysis. The geometry of each supramolecular framework was optimized by employing the PM6 semi-empirical molecular orbital method to predict its shape and size. The ability of the pyrazine-based organoplatinum complex to act as a host for nitroaromatic guest (2,4-dinitrotoluene and PA) molecules was explored by isothermal titration calorimetry (ITC). The binding stoichiometry and thermodynamic parameters of these host guest complexation reactions were evaluated using ITC. Theoretical calculations were performed to obtain insight into the binding pattern between the organometallic host and nitroaromatic guests. The preferable binding propensity of the binding sites of complex 1 for both nitroaromatics (PA and 2,4-dinitrotoluene) determined by molecular simulation studies corroborates well with the experimental results as obtained by ITC experiments.</p>1 aBhowmick, Sourav1 aChakraborty, Sourav1 aDas, Atanu1 aRajamohanan, P., R.1 aDas, Neeladri  uhttp://library.ncl.res.in/content/pyrazine-based-organometallic-complex-synthesis-characterization-and-supramolecular-002703nas a2200253   4500008004100000022001400041245012700055210006900182260000800251300001400259490000700273520183800280653002002118653002702138653002202165653001902187653002402206653001402230100002202244700002202266700001502288700002402303856012202327       2024                        eng d  a1948-719300aPathological mutations D169G and P112H electrostatically aggravate the amyloidogenicity of the functional domain of TDP-430 aPathological mutations D169G and P112H electrostatically aggrava  cNOV  a4267-42830 v153 a<p>
	Aggregation of TDP-43 is linked to the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Notably, electrostatic point mutations such as D169G and P112H, located within the highly conserved functional tandem RNA recognition motif (RRM) domains of the TDP-43 protein (TDP-43tRRM), have been identified in diseased patients as well. In this study, we address how the electrostatic mutations alter both the native state stability and aggregation propensity of TDP-43tRRM. The mutants D169G and P112H show increased chemical stability compared to the TDP-43tRRM at physiological pH. However, at low pH, both the mutants undergo a conformational change to form amyloid-like fibrils, though with variable rates-the P112H mutant being substantially faster than the other two sequences (TDP-43tRRM and D169G mutant) showing comparable rates. Moreover, among the three sequences, only the P112H mutant undergoes a strong ionic strength-dependent aggregability trend. These observations signify the substantial contribution of the excess charge of the P112H mutant to its unique aggregation process. Complementary simulated observables with atomistic resolution assign the experimentally observed sequence-, pH-, and ionic strength-dependent aggregability pattern to the degree of thermal lability of the mutation site-containing RRM1 domain and its extent of dynamical anticorrelation with the RRM2 domain whose combination eventually dictate the extent of generation of aggregation-prone partially unfolded conformational ensembles. Our choice of a specific charge-modulated pathogenic mutation-based experiment-simulation-combination approach unravels the otherwise hidden residue-wise contribution to the individual steps of this extremely complicated multistep aggregation process.</p>
10aamyloid fibrils10aconformational changes10adisease mutations10aelectrostatics10aProtein aggregation10astability1 aPillai, Meenakshi1 aPatil, Anjali, D.1 aDas, Atanu1 aJha, Santosh, Kumar  uhttp://library.ncl.res.in/content/pathological-mutations-d169g-and-p112h-electrostatically-aggravate-amyloidogenicity