Advances in biological solid state NMR : proteins and membrane active peptides The complexity and heterogeneity of biological systems has posed an immense challenge in recent years. An increasingly important tool for obtaining molecular and atomic scale information on a range of large biological molecules and cellular components is solid state NMR. This technique can address fascinating problems in structural biology including the arrangement of supramolecular complexes and fibril formation in relation to molecular folding misfolding and aggregation