Keratin keeps the coiled-coil structure is hydrophobic interactions between apolar residues along the keratins helical segments. Limited interior space is the reason why the triple helix of the (unrelated) structural protein collagen, found in skin, cartilage and bone, likewise has a high percentage of glycine. The connective tissue protein elastin also has a high percentage of both glycine and alanine. Silk fibroin, considered a β-keratin, can have these two as 75–80% of the total, with 10–15% serine, with the rest having bulky side groups. The chains are antiparallel, with an alternating C → N orientation. A preponderance of amino acids with
Myosin the retina and cochlea. Myosin IV has a single IQ motif and a tail that lacks any coiled-coil forming sequence. It has homology similar to the tail domains of Myosin VII and XV. Myosin V is an unconventional myosin motor, which is processive as a dimer and has a step size of 36 nm. It translocates (walks) along actin filaments traveling towards the barbed end (+ end) of the filaments. Myosin V is involved in the transport of cargo (e.g. RNA, vesicles, organelles, mitochondria) from the center of the cell to the periphery, but has been furthermore shown to act