1. School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
2. Institute for Discovery, University College Dublin, Belfield, Dublin 4, Ireland
3. Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
4. Laboratory of Computational Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA