An ability to optically modulate the interactions of surfaces with functional biomolecules provides an important basis for generating new technologies including reversible biosensors, advanced medical implants, and biomolecular computers. Here we report the first example of reversible photoregulation of binding of a protease to a functional surface. A modular approach is presented with a surface-bound inhibitor containing a photoisomerizable azobenzene core to which is attached (i) appropriate protease binding functionality and (ii) a tether for surface attachment. The principle is demonstrated for alpha-chymotrypsin using a phenylalanine-based trifluoromethylketone inhibitor containing an azobenzene core and an alkyne-functionalized ethylene glycol tether, which is attached to the surface using click chemistry. UV/vis irradiation of the functional surface leads to a significant, reversible change in the amount of alpha-chymotrypsin that attaches to the surface, as measured by surface plasmon resonance.

Eukaryotic cell surfaces are decorated with a complex array of glycoconjugates that are usually capped with sialic acids, a large family of over 50 structurally distinct nine-carbon amino sugars, the most common member of which is N-acetylneuraminic acid. Once made available through the action of neuraminidases, bacterial pathogens and commensals utilise host-derived sialic acid by degrading it for energy or repurposing the sialic acid onto their own cell surface to camouflage the bacterium from the immune system. A functional sialic acid transporter has been shown to be essential for the uptake of sialic acid in a range of human bacterial pathogens and important for host colonisation and persistence. Here, we review the state-of-play in the field with respect to the molecular mechanisms by which these bio-nanomachines transport sialic acids across bacterial cell membranes.

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An exploration of the chemistry of the spiro-mamakone system, exemplified by the cytotoxic, fungal metabolite spiro-mamakone A, is presented. The first reported synthesis of the spiro-mamakone carbon skeleton was achieved, as well as the synthesis of a variety of closely related analogues of the natural product. Biological testing of the synthetic analogues generated a structure-activity profile for the natural product, establishing the importance of the enedione moiety to biological activity.

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