Topological characteristics of helical repeat proteins

The recent elucidation of protein structures based upon repeating amino aci d motifs, including the armadillo motif, the HEAT motif and tetratricopepti de repeats, reveals that they belong to the class of helical repeat protein s, These proteins share the common property of being assembled from tandem repeats of an alpha-helical structural unit, creating extended superhelical structures that are ideally suited to create a protein recognition interfa ce.