ASC2 Structure has been well defined by 1141 NOE experimental restraints. The model consists of five alpha helices. alpha-Helices are connected by short random Structure loops. The sole exception is the loop connecting helices 2 and 3, which has a 20-residue length. Folding generally agrees with the folding of recently published death domain structures in Which alpha-helix Structures have been reported. In spite of structural similarity, amino acid sequence homology with the most similar protein (ASCI) is just 64%. DD, DED, and CASP protein structures present six helices along their sequences; ASC2 presents 5 well-defined helices due to long distance restraints. However, a helical fragment was observed between amino acids 38 and 42 (representing helix 3) in the death domains when constructing the model. (c) 2005 Elsevier Inc. All rights reserved.