Ri Friday evening discourse
In February, Sylvia gave a Friday evening discourse at the Royal Institution of Great Britain about the group's work into water's role in protein and peptide folding.  The video of the talk is available on the Ri YouTube Channel.

 


Part II leaving dinner
In May we said goodbye to Part II students, Imogen Duffy and Rachel McCann who have just completed and defended their MBiochem dissertations! We will miss you in the lab - goodbye and good luck.



New paper published Salt interactions in solution prevent urea from direct association with a peptide backbone

Nicola, in collaboration with Chris Lorenz and Anna Genina of King's College London, has just published a paper on the influence of co-solutes on urea-caused protein denaturation in The Journal of Physical Chemistry B.  This study shows that direct urea contacts to the model peptide KGPGK are obstructed by salt contacts and, conversely, urea lowers charged interactions of the salt molecules with the peptide or each other.

These results shed light on the complex interaction between stabilizing and destabilizing effects of co-solutes on protein folding. Specifically, it might unify existing theories of direct and indirect urea-caused protein denaturation. At higher salt concentrations and low urea concentration urea appears to influence co-solutes around the peptide backbone while at higher urea concentrations, there is a direct hydrogen bonding between urea and peptide.

Nearest neighbour water (cyan) and trifluoroacetic acid (magenta) density around the N4 peptide backbone nitrogen on KGPGK; without urea (left) and with urea (right).

New paper published On the structure of an aqueous propylene glycol solution

Natasha, in an on-going collaboration to understand the effects of solvents on drug delivery in solution with Jayne Lawrence of King's College London, has just published a paper on the structure of propylene glycol in aqueous solution in The Journal of Chemical Physics.  From this work, the propylene glycol molecules (PG) are heavily hydrated by the surrounding water solvent both by virtue of hydroxyl-water coordination but also by water association with the methyl groups on the PG molecules. 

Nearest neighbour hydration around the two PG -OH groups in aqueous solution

These hydration interactions are dominant over the PG-PG interactions as there is no evidence of extended PG structures being formed within the solution.  This may translate into a preference of PG to bind to lipid head groups rather than to itself, perhaps providing an explanation as to how PG is able to enhance the apparent solubility of some drugs for delivery in vivo.  Natasha is currently extending this investigation to directly probe the interactions between PG and the phosphatidyl choline headgroup in solution.

g(r) database
We have a database for neutron diffraction data from liquids from our investigations, where we have uploaded both RDFs (g(r)s) and S(Q)s from our recent publications here.  If you are interested in adding some published data to our current data base, and we hope you are, please contact Sylvia at
sylvia.mclain@bioch.ox.ac.uk




                                                                                                                                            
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