The correct three-dimensional structure is essential, and the misfolding of proteins can give rise to diseases such as sickle cell anaemia and is implicated in the occurrence of Alzheimer’s. However, the mechanism by which proteins fold is not well understood.
In particular, in solution it is unclear whether the presence of particular amino acids initiates the folding process or whether water plays an active role. A group of scientists from the University of Oxford and King's College London have used the SANDALS instrument at ISIS to discover the role water plays in protein folding. Their results have been published in the journal Angewandte Chemie.
Using neutron diffraction enhanced by isotopic substitution (NDIS) coupled with NMR and computational techniques, the researchers investigated a frequently occurring amino acid sequence which is known to instigate a turning motif in fully-folded functional proteins called the β-turn fold.
Dr Sylvia McLain and Dr Sebastian Busch from the University of Oxford led the study. Dr McLain says, “For the system we studied, hydrogen-bonding interactions appear to be the primary driving force in initiating the common β-turn fold. It is highly likely that hydrophilic forces are just as important in driving protein folding as the hydrophobic effect in solution, especially for the initiation of this process in vivo.”
Research date: October 2013
Water mediation essential to nucleation of β-turn formation in peptide folding motifs, Sebastian Busch, Chrystal D. Bruce, Christina Redfield, Christian D. Lorenz and Sylvia E. McLain, Angewandte Chemie In press (2013)