Through studies on the fluorescence quenching of P3’–P6’ by Rubredoxin, the extent of quenching was found to be stronger in the polymer with more typical features of helix conformation.
In a pennaceous feather, the barbs grow helically around the tubular feather germ and fuse on one side to form the rachis.Simultaneously, new barb ridges form on the other side of the tube.