Membrane proteins play a central role for the recognition and binding of modulators and associated proteins. Due to difficulties in overexpression and crystallization, their tertiary structure is often predicted using computational methods. Secondary structure elements can already be modelled with high reliability. However, no tool has been available to predict the spatial conformation of loops in membrane proteins so far.


SuperLooper provides an online interface for the automatic, quick and interactive search and placement of loops in proteins. Loop candidates are selected from a database (LIMP) comprising loops of membrane proteins or, alternatively, from (LIP) containing segments of water-soluble proteins with lengths up to 35 residues. In addition to several filtering criteria regarding structural and sequence features, the software allows for placing the loop within the predicted membrane-water interface.