1.Expression, purification, crystallization and preliminary X-ray diffraction analysis of acylpeptide hydrolase from Deinococcus radiodurans.
Are VN1, Ghosh B1, Kumar A1, Yadav P1, Bhatnagar D2, Jamdar SN3, Makde RD1. Acta Crystallogr F Struct Biol Commun. 2014 Sep;70(Pt 9):1292-5. doi: 10.1107/S2053230X14017944. Epub 2014 Aug 27.
Acylpeptide hydrolase (APH; EC 188.8.131.52), which belongs to the S9 family of serine peptidases (MEROPS), catalyzes the removal of an N-acylated amino acid from a blocked peptide. The role of this enzyme in mammalian cells has been suggested to be in the clearance of oxidatively damaged proteins as well as in the degradation of the β-amyloid peptides implicated in Alzheimer's disease. Detailed structural information for the enzyme has been reported from two thermophilic archaea; both of the archaeal APHs share a similar monomeric structure. However, the mechanisms of substrate selectivity and active-site accessibility are totally different and are determined by inter-domain flexibility or the oligomeric structure. An APH homologue from a bacterium, Deinococcus radiodurans (APHdr), has been crystallized using microbatch-under-oil employing the random microseed matrix screening method. The protein crystallized in space group P21, with unit-cell parameters a = 77.
2.Interaction between functionalized gold nanoparticles in physiological saline.
Alsharif SA1, Chen LY, Tlahuice-Flores A, Whetten RL, Yacaman MJ. Phys Chem Chem Phys. 2014 Mar 7;16(9):3909-13. doi: 10.1039/c3cp54503b.
The interactions between functionalized noble-metal particles in an aqueous solution are central to applications relying on controlled equilibrium association. Herein, we obtain the potentials of mean force (PMF) for pair-interactions between functionalized gold nanoparticles (AuNPs) in physiological saline. These results are based upon >1000 ns experiments in silico of all-atom model systems under equilibrium and non-equilibrium conditions. Four types of functionalization are built by coating each globular Au144 cluster with 60 thiolate groups: GS-AuNP (glutathionate), PhS-AuNP (thiophenol), CyS-AuNP (cysteinyl), and p-APhS-AuNP (para-amino-thiophenol), which are, respectively, negatively charged, hydrophobic (neutral-nonpolar), hydrophilic (neutral-polar), and positively charged at neutral pH. The results confirm the behavior expected of neutral (hydrophilic or hydrophobic) particles in a dilute aqueous environment, however the PMF curves demonstrate that the charged AuNPs interact with one another in a unique way-mediated by H2O molecules and an electrolyte (Na(+), Cl(-))-in a physiological environment.
3.Spectroscopic investigation of photoinduced charge-transfer processes in FTO/TiO2/N719 photoanodes with and without covalent attachment through silane-based linkers.
Pandit B1, Luitel T, Cummins DR, Thapa AK, Druffel T, Zamborini F, Liu J. J Phys Chem A. 2013 Dec 19;117(50):13513-23. doi: 10.1021/jp407270j. Epub 2013 Nov 6.
Understanding electron-transfer (ET) processes in dye-sensitized solar cells (DSSCs) is crucial to improving their device performance. Recently, covalent attachment of dye molecules to mesoporous semiconductor nanoparticle films via molecular linkers has been employed to increase the stability of DSSC photoanodes. The power conversion efficiency (PCE) of these DSSCs, however, is lower than DSSCs with conventional unmodified photoanodes in this study. Ultrafast transient absorption pump-probe spectroscopy (TAPPS) has been used to study the electron injection process from N719 dye molecules to TiO2 nanoparticles (NPs) in DSSC photoanodes with and without the presence of two silane-based linker molecules: 3-aminopropyltriethoxysilane (APTES) and p-aminophenyltrimethoxysilane (APhS). Ultrafast biphasic electron injection kinetics were observed in all three photoanodes using a 530 nm pump wavelength and 860 nm probe wavelength. Both the slow and fast decay components, attributed to electron injection from singlet and triplet excited states, respectively, of the N719 dye to the TiO2 conduction band, are hindered by the molecular linkers.
4.Influence of non-steroidal anti-inflammatory drugs on Drosophila melanogaster longevity.
Danilov A1,2, Shaposhnikov M2,3, Shevchenko O2, Zemskaya N2, Zhavoronkov A4, Moskalev A1,2,3,5. Oncotarget. 2015 Aug 14;6(23):19428-44.
Most age-related diseases and aging itself are associated with chronic inflammation. Thus pharmacological inhibition of inflammatory processes may be effective antiaging strategy. In this study we demonstrated that treatment of Drosophila melanogaster with 10 non-steroidal anti-inflammatory drugs (NSAIDs: CAY10404, aspirin, APHS, SC-560, NS-398, SC-58125, valeroyl salicylate, trans-resveratrol, valdecoxib, licofelone) leads to extension of lifespan, delays age-dependent decline of locomotor activity and increases stress resistance. The effect of the lifespan increase was associated with decrease of fecundity. Depending on the concentration, NSAIDs demonstrated both anti- and pro-oxidant properties in Drosophila tissues. However, we failed to identify clear correlation between antioxidant properties of NSAIDs and their pro-longevity effects. The lifespan extending effects of APHS, SC-58125, valeroyl salicylate, trans-resveratrol, valdecoxib, and licofelone were more pronounced in males, valdecoxib and aspirin - in females.