Articles in 2011

Activating caged reactive sites in proteins using mechanical force provides a powerful approach in the study of chemical reactions, and provides greater insight into which reactions are possible and their rates.

Proton migration on membranes is a crucial step in the bioenergetics of the cell. It has typically been regarded as slow successive proton transfers between ionizable moieties within the membrane, but recent measurements suggest fast lateral diffusion in the membrane's hydration layer.

A tetra-intercalator compound that threads through a DNA double-helix to form a remarkably stable complex exhibits an unusual combination of sequence specificity and rapid association yet slow dissociation.

Topological insulators — insulators or semiconductors with metallic states present at their boundaries — are the 'rising stars' of condensed-matter physics. This Perspective introduces these materials and their properties, and looks at the challenges and opportunities the community faces.

Intracellular biothiols can degrade nanoparticle monolayers, compromising the function of these potentially promising tools. Here, we describe a label-free method for quantifying the intracellular stability of quantum dot monolayers, using laser desorption/ionization mass spectrometry coupled with inductively coupled plasma mass spectrometry.

Cell-laden synthetic hydrogels — formed via a copper-free click reaction between a poly(ethylene glycol) tetra-cyclooctyne and a peptide-diazide — provide a platform to investigate the cells' response to various stimuli during growth. The hydrogel's biochemical aspects are readily controlled by a thiol-ene photocoupling reaction initiated with visible light, whereas the biomechanical properties of the network are altered via a UV-mediated photodegradation.

The natural product fumagillol has been exploited as a stereochemically rich scaffold for the synthesis of a structurally unique, chemically diverse library with chemotypes distinctly different from the parent structure. Thus, fumagillol has been remodelled into a diverse array of isoindoles, isoquinolines, furans, mopholinones and benzoxazepines.

The polyprenylated polycyclic acylphloroglucines (PPAPs) are a family of natural products in which a common core is decorated with four different substituents. Here, a synthetic strategy is presented that separates the core building steps from the core decorating steps, offering a general solution to the synthesis of these natural products that will allow investigation of their biological activities.

Multiple redox reaction pathways exist in proteins containing several cysteines. A technique termed mechanical uncaging is now demonstrated, allowing the release of a single reactive cysteine within a protein and the unequivocal observation of subsequent thiol/disulfide exchanges. Mechanical uncaging of reactive groups is useful for studying chemical kinetics in a synchronized manner.

Cellular membrane lipids play key roles in cell regulation. Here, an environmentally sensitive fluorophore is attached to a protein that binds to a key signalling lipid to produce a membrane lipid sensor. This strategy allows sensitive, quantitative, spatiotemporal imaging of the lipid concentration in mammalian cells.

At water's surface, its network of hydrogen-bonds is abruptly interrupted, conferring distinct properties on interfacial water from bulk water. Understanding aqueous interfaces is essential for many environmental, technological and biophysical systems, and now the pathways and rates of energy transfer at the water/air interface are elucidated using a surface-specific ultrafast spectroscopic technique.

The flow of vibrational energy into reactants and out of products plays a critical role in nearly every chemical reaction. Here, a time-resolved ultrafast microscopic map of energy flow is provided for a thermal bimolecular chemical reaction that takes place in dichloromethane, a typical organic solvent.

Stereoselective Suzuki–Miyaura cross-coupling reactions involving non-benzylic secondary alkylboronates are notoriously challenging. Here, an enantioselective synthesis of 1,1-diboronyl compounds using asymmetric conjugate borylation, followed by chemoselective mono cross-coupling with inversion at the diboron centre, is used to produce highly enantioenriched benzylic or allylic boronates, which themselves are useful reagents for a number of processes.

Molecules that bind to DNA for extended periods can modulate its transcription or other biological processes. Kinetic studies on the non-covalent complex formed by a threading tetra-intercalator and a DNA double-helix have now revealed a multi-step association, and a particularly slow dissociation leading to sequence specificity and a 16-day half-life.