Detalle de: Protein Superfamilies

The concept of ‘superfamily’ is key for understanding the organisation of the protein universe and extracting useful information from it. As a set of proteins with a common ancestor, a superfamily contains rich information on the structural, functional and evolutionary features of its members. It represents a good equilibrium between conservation and variability. In one hand, the members of a superfamily have the same global 3D structure, can be aligned, and share many functional aspects. On the other hand, they are variable enough to encode important information on the functional diversity of their members. This variability also allows generating informative profiles which can be used to pick up distant relatives (e.g. to predict their function or their 3D structure). For these reasons, the concept of superfamily is behind many modern approaches for studying and predicting protein function and structure. The available massive data on protein superfamilies is accessible through a number of web resources. Key Concepts: A superfamily is a group of protein domains arisen from a common ancestor, being such common origin evident in their sequence identities or not. The superfamily is the most informative level of protein classification hierarchies. The concept of superfamily is behind most methods for predicting protein structure and function. All available information on protein superfamilies is available online in dedicated web sites. The rate of ‘discovery’ of new superfamilies is decaying and some people think that we might be close to having ‘touched’ most superfamilies of the protein universe.