Description of the local protein structure. I. Classical approaches.
Résumé
The analysis and visualisation of protein 3D structures is often limited to the succession of repetitive local structures, i.e. the Α-helices and the Β-sheets connected by non-repetitive structures, i.e. the coil. This description in terms of secondary structure is widely used, but can bring to forget some features: (i) the definition of Α-helices and Β-sheets is already a difficult task, and, (ii) beyond these two repetitive structures, others interesting local folds can be described and are useful to analyze the 3D protein structures. In this review, we present the classical repetitive secondary structures as well as other structural motifs described in the literature that provide a more precise description of 3D structures. Then, we show the difficulties of secondary structure assignment.