Molecular assembly lines, where molecules undergo iterative processes involving chain elongation and functional group manipulation are hallmarks of many processes found in Nature. We have sought to emulate Nature in the development of our own molecular assembly line through iterative homologations of boronic esters. Here we report a reagent (α-lithioethyl triispopropylbenzoate) which inserts into carbon-boron bonds with exceptionally high fidelity and stereocontrol. Through repeated iteration we have converted a simple boronic ester into a complex molecule (a carbon chain with ten contiguous methyl groups) with remarkably high precision over its length, its stereochemistry and therefore its shape. Different stereoisomers were targeted and it was found that they adopted different shapes (helical/linear) according to their stereochemistry. This work should now enable scientists to rationally design and create molecules with predictable shape, which could have an impact in all areas of molecular sciences where bespoke molecules are required.

Gaucher disease has recently received wide attention due to the unexpected discovery that it is a genetic risk factor for Parkinson's disease. Gaucher disease is caused by the defective activity of the lysosomal enzyme, glucocerebrosidase (GCase; GBA1), resulting in intracellular accumulation of the glycosphingolipids, glucosylceramide and psychosine. The rare neuronopathic forms of GD (nGD) are characterized by profound neurological impairment and neuronal cell death. We have previously described the progression of neuropathological changes in a mouse model of nGD. We now examine the relationship between glycosphingolipid accumulation and initiation of pathology at two pre-symptomatic stages of the disease in four different brain areas which display differential degrees of susceptibility to GCase deficiency. Liquid chromatography electrospray ionization tandem mass spectrometry demonstrated glucosylceramide and psychosine accumulation in nGD brains prior to the appearance of neuroinflammation, although only glucosylceramide accumulation correlated with neuroinflammation and neuron loss. Levels of other sphingolipids, including the pro-apoptotic lipid, ceramide, were mostly unaltered. Transmission electron microscopy revealed that glucosylceramide accumulation occurs in neurons, mostly in the form of membrane-delimited pseudo-tubules located near the nucleus. Highly disrupted glucosylceramide-storing cells, which are likely degenerating neurons containing massive inclusions, numerous autophagosomes and unique ultrastructural features, were also observed. Together, our results indicate that a certain level of neuronal glucosylceramide storage is required to trigger neuropathological changes in affected brain areas, while other brain areas containing similar glucosylceramide levels are unaltered, presumably because of intrinsic differences in neuronal properties, or in the neuronal environment, between various brain regions.

No abstract

The use of molecular dynamics (MD) calculations to derive relative populations of conformers is highly sensitive to both timescale and parameterisation of the MD. Where these calculations are coupled with NOE data to determine the dynamics of a molecular system, this can present issues if these populations are thus relied upon. We present an approach that refines the highly accurate PANIC NMR methodology combined with clustering approaches to generate conformers, but without restraining the simulations or considering the relative population distributions generated by MD. Combining this structural sampling with NOE fitting, we demonstrate, for S-adenosylmethionine (aqueous solution at pH 7.0), significant improvements are made to the fit of populations to the experimental data, revealing a strong overall preference for the syn conformation of the adenosyl group relative to the ribose ring, but with less discrimination for the conformation of the ribose ring itself.

An Alkanna orientalis leaf and flower extract inhibited the growth of Staphylococcus aureus, a pathogen that causes an estimated 478,000 hospitalizations in the US annually. Bioassay-guided fractionation of A. orientalis resulted in isolation of the flavonoid sarothrin (5,7,4′-trihydroxy-3,6,8-trimethoxyflavone), which inhibited the growth of Mycobacterium smegmatis (MIC 75 μM) and S. aureus (MIC >800 μM), and possessed efflux pump inhibitory activity. This is the first report of antimicrobial or efflux pump inhibitory activity of sarothrin, and of its presence in A. orientalis. Our findings suggest that the effectiveness of A. orientalis extracts is due to a combination of multiple constituents, including sarothrin.

NOE-distance relationships are shown to be sufficiently accurate to monitor very small changes in conformer populations in response to temperature (<0.5%/10 °C) - in good agreement with Boltzmann-predictions, illustrating the effectiveness of accurate NOE-distance measurements in obtaining high quality dynamics as well as structural information for small molecules.

Polyoxopalladates (POPs) are a class of selfassembling palladium-oxide clusters that span a variety of sizes, shapes and compositions. The largest of this family, {Pd 84 } Ac , is constructed from 14 building units of {Pd 6 } and lined on the inner and outer torus by 28 acetate ligands. Due to its high water solubility, large hydrophobic cavity and distinct 1 H NMR fingerprint {Pd 84 } Ac is an ideal molecule for exploring supramolecular behaviour with small organic molecules in aqueous media. Molecular visualisation studies highlighted potential binding sites between {Pd 84 } Ac and these species. Nuclear Magnetic Resonance (NMR) techniques, including 1 H NMR, 1 H Diffusion Ordered Spectroscopy (DOSY) and Nuclear Overhauser Spectroscopy (NOESY), were employed to study the supramolecular chemistry of this system. Here, we provide conclusive evidence that {Pd 84 } Ac forms a 1 : 7 host-guest complex with benzyl viologen (BV 2 + ) in aqueous solution.

<p><b>The search for evidence of life elsewhere in the universe is hard because it is not obvious what signatures are unique to life. Here we postulate that complex molecules found in high abundance are universal biosignatures as they cannot form by chance. To explore this, we developed the first intrinsic measure of molecular complexity that can be experimentally determined, and this is based upon a new approach called assembly theory which gives the molecular assembly number (MA) of a given molecule. MA allows us to compare the intrinsic complexity of molecules using the minimum number of steps required to construct the molecular graph starting from basic objects, and a probabilistic model shows how the probability of any given molecule forming randomly drops dramatically as its MA increases. To map chemical space, we calculated the MA of <i>ca.</i> 2.5 million compounds, and collected data which showed the complexity of a molecule can be experimentally determined by using three independent techniques including infra-red spectroscopy, nuclear magnetic resonance, and by fragmentation in a mass spectrometer, and this data has an excellent corelation with the values predicted from our assembly theory. We then set out to see if this approach could allow us to identify molecular biosignatures with a set of diverse samples from around the world, outer space, and the laboratory including prebiotic soups. <a>The results show that </a><a>there is a non-living to living threshold in MA complexity and the higher the MA for a given molecule, the more likely that it had to be produced by a biological process</a>. This work demonstrates it is possible to use this approach to build a life detection instrument that could be deployed on missions to extra-terrestrial locations to detect biosignatures, map the extent of life on Earth, and be used as a molecular complexity scale to quantify the constraints needed to direct prebiotically plausible processes in the laboratory. Such an approach is vital if we are going to find new life elsewhere in the universe or create <i>de-novo</i> life in the lab. </b></p>