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Guest post from Tom Branson
The taste of sweet success! But what is that flavour exactly, chewing gum or bon bons? The latest Organic & Biomolecular Chemistry (OBC) issue comes covered with sugary carbohydrate goodness and fullerene balls. Not at first obvious partners but throw in some lectins and you’ve got a hit.
On the cover a gumball machine has been set up in the lab with a few of the tasty C60 balls spilling out across the bench. The test tubes arranged at the back signify that the green, blue, red and yellow balls are obviously full of artificial colourings to make them tempting, but these are not for human consumption. In fact they are meant for bacterial consumption.
The bacteria in question produce fucose binding proteins, carbohydrate receptors that can be targeted for therapeutic reasons. On the cover, a schematic has been left out on the lab bench showing the fullerenes modified with linkers and terminating in fucose units, which then have a multivalent effect binding to one or more of the proteins.
The work focuses on the inhibition of two fucose binding proteins with very different binding site geometries. LecB is your typical brick–like protein with four binding sites (one at each corner), whilst RSL is a hexamer ring with 6 binding sites positioned around the bottom face of the hoop. So what binds best to these different sugar hungry proteins? The modified fullerenes can be used to present the sugars in a wide display and after testing different spacer lengths and different valencies they found that, contrary to most medical advice, more sugar was generally better. But only generally – because it depends on the geometry of the binding sites, matching this display also your helps your cause. And if there are too many binding units then it can get too crowded and nobody can get their hands on the sugary groups. Therefore, presentation, arrangement and quantity are all important for attracting the most guests to your desert table.
Not one but two delightful treats were conceived by the authors for showing off their sugary balls. The digital abstract focuses on a set of fullerene based cakes. I wonder if there was competition in the lab as to which recipe would make it to the cover? Cakes and other sticky treats are often used to highlight carbohydrate/sugar research and offer one of many simple means to entice public interest. My old (in the sense of in the past, not by age I hasten to add) PhD supervisor, Bruce Turnbull, shows off his research and his lab’s sweet tooth with the traditional group cake bakeoff, now a modest Twitter sensation. And check out this great YouTube video starting with the sugar in your cup of tea and ending with fertilisation.
Funding for this publication was partly provided by the European COST action MultiGlycoNano, which I was also fortunate to benefit from during my time at university. This European money pot took me to Holland, Italy and France, the latter being where I actually first met Anne Imberty, one of the authors of this study, and heard her talk about lectin binding. My own research on protein-carbohydrate interactions was very close to this subject, although not referenced by this OBC paper (come on Anne; do my H-index a favour!)
The paper is marked as a Hot Article in OBC, which means that it is free to read for the next 4 weeks. So go go go read it now before you have to pay and before the bacteria get their receptors all over those gumballs.
Jean-François Nierengarten, one of the authors of the OBC paper, sent us some extra pictures of chemical confectionery (fondant fullerenes?) with the following explanation:
You may be interested by the story behind this picture. One post-doc of the group, Sebastian Guerra, has shown the picture to his father in law, Mr Pellaton, he is the owner of a chocolate shop in a small Swiss village (Peseux). After a couple of weeks, the fullerene-shaped chocolate became reality, a quite unexpected application of our research project on fullerene sugar balls. Of course, the prototype did not survive a long time at home when my son realized that the fullerene ball was made from real chocolate!
Tom Branson is wondering if there was a competition in the lab as to which recipe would make it to the cover. Actually, it was not the case. During my spare time, I enjoy preparing 3D figures with Cheetah3D (a fantastic software for Mac). I had the one with the chocolate ready at the time we submit the paper (I’m using it for my lectures) and following the invitation to prepare the cover, I had simply an excuse to prepare a new figure!
As an additional example, I have enclosed a figure I’m using to illustrate a very recent Chem. Sci. paper in my lectures: