Rop protein: Difference between revisions

Rop is the paradigm of a canonical 4-α-helical bundle and its apparent structural simplicity of its folding rendered it as model system to investigate the sequence-structure relationships in the folding and dynamics of 4-α-helix. The four α-helices are amphipathic, pack in an antiparallel fashion and display a specific pattern of hydrophobic and hydrophilic amino acids, of the type (a,b,c,d,e,f,g)n, which is repeated every seven residues (heptad pattern). Positions a and d are generally hydrophobic and the side chains of these residues are packed in the central part of the structure according to the “knobs in holes” model forming the hydrophobic core. The heptad periodicity in the sequence of Rop is disrupted only once and leads to the formation of the loop. <scene name='Rop_protein/Wt_rop_a31/2'>Ala31</scene> has a crucial role in the formation of the loop region as it is the only amino acid that simultaneously forms hydrogen bond to both helices.