The overall objective of our research is to understand the principles governing protein homeostasis - the ability of cells to generate and regulate the levels of proteins in terms of conformations, interactions, concentrations and cellular localisation. By adopting the strategy of analysing the origins of specific diseases to inform us about normal biology, we have set up an interdisciplinary programme that involves bringing together methods and concepts from chemistry, physics, engineering, genetics and medicine. We are using a combination of in vitro, in silico and in vivo approaches to study protein homeostasis through the analysis of the effects that result from its alteration in a select group of specific proteins, from either amino acid mutations, or changes in concentration and solubility, or the interactions with other molecules. This programme is generating new insights into the mechanism through which physical and chemical sciences can address biological questions in order to understand the normal behaviour of living systems. In addition it is increasing our understanding of the nature and consequences of the failure to maintain homeostasis, which is associated with such phenomena as ageing and neurodegenerative disorders.



LATEST RESEARCH


Structure of a low-population intermediate state in the release of an enzyme product. eLife (2015)

Enzymes can increase the rate of biomolecular reactions by several orders of magnitude. Although the steps of substrate capture and product release are essential in the enzymatic process, complete atomic-level descriptions of these steps are difficult to obtain because of the transient nature of the intermediate conformations, which makes them largely inaccessible to standard structure determination methods. We describe here the determination of the structure of a low-population intermediate in the product release process by human lysozyme through a combination of NMR spectroscopy and molecular dynamics simulations. We validate this structure by rationally designing two mutations, the first engineered to destabilise the intermediate and the second to stabilize it, thus slowing down or speeding up, respectively, product release. These results illustrate how product release by an enzyme can be facilitated by the presence of a metastable intermediate with transient weak interactions between the enzyme and the product.


A molecular chaperone breaks the catalytic cycle that generates toxic Abeta oligomers. Nat. Struct. Mol. Biol. (2015)

Alzheimer's disease is a highly debilitating and increasingly prevalent neurodegenerative disorder whose pathogenesis has been associated with the aggregation of the amyloid-beta peptide (Abeta42). Recent studies have revealed that the formation of highly neurotoxic oligomers during Abeta aggregation is strongly catalysed by the surfaces of larger aggregates. These findings indicate that a particularly effective way to limit Abeta42 toxicity would be through agents that inhibit this catalytic cycle. Here we show that a molecular chaperone, a Brichos domain, has the ability to specifically block the catalytic production of oligomers. We further demonstrate by a series of biophysical techniques that the Brichos domain achieves this inhibition in vitro by binding on the surface of the fibrils and redirecting the reactive flux from the monomeric to the fibrillar states via a pathway that involves a minimal formation of toxic oligomeric intermediates. We then verify by means of cytotoxicity and electrophysiology experiments using brain tissue that this mechanism also occurs in vivo. These results suggest that biological systems have evolved to achieve effective and efficient suppression of the toxic effects of protein misfolding and aggregation by targeting the individual microscopic pathways that create toxic oligomers, rather than perturbing the overall aggregation reaction.

NEW TOOLS


CamSol: A method of rational design of protein variants with enhanced solubility.

Web server (academic)

Web server (non academic)



P. Sormanni, F. A. Aprile and M. Vendruscolo. J. Mol. Biol. 427, 478-490 (2015).



NEW TOOLS


The s2D method: Simultaneous sequence-based prediction of the statistical populations of ordered and disordered regions in proteins

Web server




P. Sormanni, C. Camilloni, P. Fariselli and M. Vendruscolo.
J. Mol. Biol. 427, 982-996 (2015).



BOOKS


Networks in Cell Biology



M. Buchanan, G. Caldarelli, P. De Los Rios, F. Rao and M. Vendruscolo (Eds). Cambridge University Press, Cambridge (2010).