Poster Presentation 2014 International Biophysics Congress

Exploring curvature in-vitro on in-vivo lengthscales (#303)

Hanna M.G. Barriga 1 , Nicola McCarthy 1 , Arwen Tyler 1 , Edward Parsons 1 , John Seddon 1 , Robert V. Law 1 , Oscar Ces 1 , Nicholas Brooks 1
  1. Imperial College London, London, UK

Control of membrane curvature across a wide range of length scales plays a major role within cells. It is vital to processes ranging from regulation of protein function to vesicle trafficking1. Non lamellar structures including bicontinuous cubic phases have been observed in-vivo2 and it has been suggested that they may be critical to both cellular structure and dynamic processes. Whilst these structures have been replicated in-vitro, the length scales accessible to date are an order of magnitude smaller than those seen in-vivo3.
We have engineered bicontinuous cubic phases displaying curvature on length scales significantly above those previously reported. By using small angle X-Ray diffraction (SAXS) at Diamond Light Source, UK and ESRF, France we have been able to probe the effect of varying composition, temperature, pressure and hydration on the lattice parameters of mono-glyceride based bicontinuous cubic phases and begin to elucidate the factors that control the accessible length scales.
Many of the applications of bicontinuous cubic phases are facilitated through the use of cubosomes: dispersed nano-particles with an internal bicontinuous cubic phase structure. These have been applied in a wide range of applications ranging from protein crystallisation to drug delivery4. We are using the engineering rules developed using SAXS on bulk cubic structures to design cubosomes with targeted pore size and geometry. These are being characterised using a combination of electron microscopy and X-Ray diffraction. Rapid control of cubosome pore sizes using pressure offers the exciting prospect of forming novel tuneable platforms for protein crystallisation.

  1. H. T. McMahon, J. L. Gallop, Nature, 2005, 438, 590, ‘Membrane curvature and mechanisms of dynamic cell membrane remodelling’
  2. Y. Deng, C.A. Mannella, Journal of Structural Biology, 1999, 127 (3), 231, ‘Cubic membrane structure in amoeba (Chaos carolinesis) mitochondria determined by electron microscopic tomography’
  3. G. K. Voeltz, W. A. Prinz, Nature Reviews Molecular Cell Biology, 2007, 8, 258, ‘Sheets, ribbons and tubules – how organelles get their shape’
  4. X. Mulet, C.J. Drummond, American Chemical Society Nano, 2009, 3 (9), 2790, ‘Observing self-assembled lipid nanoparticles building order and complexity through low-energy transformation processes’