title: Alpha-helical coiled-coil oligomerization domains in extracellular proteins.
abstract: Subunit oligomerization of many proteins is mediated by alpha-helical coiled-coil domains. 3,4-Hydrophobic heptad repeat sequences, the characteristic feature of the coiled-coil protein folding motif, have been found in a wide variety of gene products including cytoskeletal, nuclear, muscle, cell surface, extracellular, plasma, bacterial, and viral proteins. Whereas the majority of coiled-coil structures is represented by intracellular alpha-helical bundles that contain two polypeptide chains, examples of extracellular coiled-coil proteins are fewer in number. Most proteins located in the extracellular space form three-stranded alpha-helical assemblies. Recently, five-stranded coiled coils have been identified in thrombospondins 3 and 4 and in cartilage oligomeric matrix protein, and the formation of a heterotetramer has been observed in in vitro studies with the recombinant asialoglycoprotein receptor oligomerization domain. Coiled-coil domains in laminins and probably also in tenascins and thrombospondins are responsible for the formation of tissue-specific isoforms by selective oligomerization of different polypeptide chains.
authors.affiliation: Department of Biophysical Chemistry, Biozentrum, University of Basel, Switzerland.
authors.forename: R A
authors.initials: RA
authors.lastname: Kammerer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D037263:Asialoglycoprotein Receptor; D002356:Cartilage; D018360:Crystallography, X-Ray; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D005110:Extracellular Space; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins / Q000737:chemistry; D008961:Models, Structural; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011956:Receptors, Cell Surface / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D019699:Thrombospondins
chemical_list: D037263:Asialoglycoprotein Receptor; D016326:Extracellular Matrix Proteins; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D019699:Thrombospondins