title: Proteinchemical characterization of three structurally distinct domains along the protofilament unit of desmin 10 nm filaments.
abstract: Limited chymotryptic cleavage of soluble chicken gizzard desmin protofilaments allows the characterization of three structurally distinct domains. A surface-exposed very basic amino-terminal region (the headpiece) with an amino acid sequence excluding alpha-helical organization (7.5 kd) is separated from the perhaps globular carboxy-terminal 48 residues (the tailpiece) by a distinctly different middle domain of approximately 330 residues. This 38 kd domain is very rich in alpha-helix (at least 83%), and electron microscopy reveals a thin rod with a length of 500 +/- 50 A. Amino acid sequence data also show that the rod domain is interrupted by a nonhelical portion. An alpha-helical array is able to form a coiled-coil spanning the carboxy-terminal half of the 38 kd domain. The alpha-type diffraction pattern of 10 nm filaments arises from a coiled-coil conformation displayed through most but not all of the middle domain of the protofilaments.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002645:Chickens; D002918:Chymotrypsin; D003599:Cytoskeleton / Q000032:analysis*; D003893:Desmin; D007381:Intermediate Filament Proteins; D011487:Protein Conformation; D013552:Swine
chemical_list: D000596:Amino Acids; D003893:Desmin; D007381:Intermediate Filament Proteins; D002918:Chymotrypsin