title: Three-dimensional structure of herring sperm protamine Y-I with the aid of dark field electron microscopy.
abstract: High resolution electron micrographs of herring sperm protamine (clupeine) Y-I provide sufficient detail to constrain the folding of the known amino-acid sequence of the protein into a unique three-dimensional configuration. The structure consists of a loose helix of turns of various sizes held together at one edge, spread apart along the other. This form appears to represent the shape of several fish protamines.
mesh_terms: D000818:Animals; D001665:Binding Sites; D003026:Clupeine; D005399:Fishes; D008297:Male; D008854:Microscopy, Electron; D008958:Models, Molecular; D011479:Protamines; D011485:Protein Binding; D011487:Protein Conformation; D013094:Spermatozoa / Q000032:analysis*
chemical_list: D011479:Protamines; D003026:Clupeine