Solution structures of oligonucleotides containing either a guanine or a cytosine in front of a gap of one nucleotide

We report NMR and molecular modelling studies on two DNA duplexes containing a gap of one nucleotides. The difference between the two oligonucleotides lies in the central base face to the gap, a guanine or a cytosine. For the gapG, we observed in solution a B-form conformation where the guanine stacks in the helix. For the gapC, we reveal the existence of two species, one majority where the cytosine is inside the helix and a second for which the cytosine is extrahelical

M3 muscarinic receptor interaction with phospholipase C beta3 determines its signaling efficiency

Contains fulltext : 133821.pdf (publisher's version ) (Open Access)Phospholipase Cbeta (PLCbeta) enzymes are activated by G protein-coupled receptors through receptor-catalyzed guanine nucleotide exchange on Galphabetagamma heterotrimers containing Gq family G proteins. Here we report evidence for a direct interaction between M3 muscarinic receptor (M3R) and PLCbeta3. Both expressed and endogenous M3R interacted with PLCbeta in coimmunoprecipitation experiments. Stimulation of M3R with carbachol significantly increased this association. Expression of M3R in CHO cells promoted plasma membrane localization of YFP-PLCbeta3. Deletion of the PLCbeta3 C terminus or deletion of the PLCbeta3 PDZ ligand inhibited coimmunoprecipitation with M3R and M3R-dependent PLCbeta3 plasma membrane localization. Purified PLCbeta3 bound directly to glutathione S-transferase (GST)-fused M3R intracellular loops 2 and 3 (M3Ri2 and M3Ri3) as well as M3R C terminus (M3R/H8-CT). PLCbeta3 binding to M3Ri3 was inhibited when the PDZ ligand was removed. In assays using reconstituted purified components in vitro, M3Ri2, M3Ri3, and M3R/H8-CT potentiated Galphaq-dependent but not Gbetagamma-dependent PLCbeta3 activation. Disruption of key residues in M3Ri3N and of the PDZ ligand in PLCbeta3 inhibited M3Ri3-mediated potentiation. We propose that the M3 muscarinic receptor maximizes the efficiency of PLCbeta3 signaling beyond its canonical role as a guanine nucleotide exchange factor for Galpha

Molecular structure studies by 3D imaging of fast ion beams

The use of the Coulomb-explosion technique combined with a radically new multi-particle detector, extremely thin film targets, and low-excitation ion source has enabled, for the first time, direct measurements of the complete stereochemistry of complex polyatomic molecular ions. We outline the methods used and present results for protonated acetylene (C/sub 2/H/sub 3//sup +/) and the methane cation (CH/sub 4//sup +/) as examples. We demonstrate the techniques by which these methods can be generalized to determine directly vibrational motions in polyatomic molecules. 24 refs., 4 figs

Effects seen in the interactions of fast molecular-ion beams with matter. [Angular distributions, dissociation, polorization, energy losses, transmitted fractions]

Experimental results are presented from high resolution studies of the energy- and angle-distributions for the break-up products that arise from the dissociation of a variety of fast molecular ions in thin carbon foils and in gases. The results for foil targets are compared with calculations based on a model for the polarization ''wakes'' induced in foils by the passage of fast charged projectiles. An example is given of the application of this type of dissociation measurement to the determination of a molecular structure--that of H/sub 3//sup +/. Also measurements on the transmission of fast molecular ions through carbon foils are described and results presented on the transmission probabilities, energy losses and angular distributions of the transmitted ions