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Theme B: Biomolecules

Biomolecules can play a significant role in the formation of nanostructured hard tissues in living organisms. These materials are formed with a degree of control that cannot yet be exerted in synthetic laboratories. To mimic these natural biomineralisation strategies, we must identify the mechanisms at work at the biomolecule-mineral interface. We will investigate, via a coupling of theory and experiment, two aspects of this interface. One aspect is how the surface can manipulate the conformation of the adsorbing biomolecule. Conformationally-labile biomolecules such as intrinsically-disordered proteins (IDPs) can change conformation upon exposure to external stimuli. Mineral surfaces provide such a stimulus that can induce folding and thus confer function(s) (such as polymorph stabilisation) related to this new conformation. Another aspect is how the adsorption of biomolecules influences the growth/stability of different crystal faces. Harnessing the ability of biomolecules to modify the growth of crystals in a controlled way remains a major challenge in materials science. This Work Package comprises three projects that will explore this interface from these two perspectives. As a result of this Work Package, we would in future be able to: design molecules with surface-specific binding properties for inhibiting the growth of wax and ice, utilise peptide sequences that can direct polymorph stabilization, and, (via eggshell geochronology) explore questions regarding early human migration.

The Challenge

There are three sub-projects to be tackled in this theme; (1) molecule-induced polymorph stabilization, (2) inhibition of crystal growth via molecular additives, and, (3) the search for conserved calcite-binding domains in eggshell proteins. Our overarching goal here is the adaptation, development and integration of a set of experimental and simulation approaches that will deliver profound new insight into the structure and dynamics of the biomolecule-mineral interface. One of the main obstacles to progress in the simulation of the biomolecule-mineral interface is the fact that adequate sampling of the biomolecule conformation can be difficult to achieve, since the effects of water structuring at these interfaces must also not be ignored.

Achievements so far: June 2013

  • identification of facet-selective binding behaviour for adsorption of biomolecules;
  • generation of the first polarizable force-field to describe the interactions between different gold facets (including reconstructed facets) and peptides described using CHARMM;
  • modification and validation of novel & efficient advanced conformational sampling (REST at interfaces) enabling bio-interface simulations of unprecedented length and time scales;
  • substantial advance in molecular understanding of small organic molecule adsorption on CaCO3, giving an excellent base for future studies on the inhibitory effect of biomolecules;
  • discovery that branching and acidity of functional groups strongly enhances the inhibition potential of polysaccharide.