title: Glomerular basement membrane. Identification of a fourth chain, alpha 4, of type IV collagen.
abstract: The noncollagenous domain hexamer of collagen IV from bovine glomerular basement membrane was further investigated to determine the types of collagen chain from which subunits M2*b and M3 are derived. M2*b was shown to be a shorter form, containing 9 fewer residues, of M2*a which was previously established as the noncollagenous domain of a third chain, alpha 3, of collagen IV (Saus, J., Wieslander, J., Langeveld, J.P.M., Quinones, S., and Hudson, B.G. (1988) J. Biol. Chem. 263, 13374-13380). M3 was identified as the noncollagenous domain of a fourth chain, alpha 4, of type IV collagen, on the basis of additional sequence data together with previous findings. A comparison of the collagenous-noncollagenous junction regions of alpha 3(IV) and alpha 4(IV) chains with those of classical alpha 1(IV) and alpha 2(IV) chains reveals structural information which provides a potential strategy for molecular cloning of these novel chains. The results further reveal the complexity of electrophoresis patterns of the hexamer and potential ambiguities in using one-dimensional patterns to determine whether molecular defects of collagen IV occur in pathological processes affecting basement membranes.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66103.
authors.forename: S
authors.initials: S
authors.lastname: Gunwar
authors.forename: J
authors.initials: J
authors.lastname: Saus
authors.forename: M E
authors.initials: ME
authors.lastname: Noelken
authors.forename: B G
authors.initials: BG
authors.lastname: Hudson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001485:Basement Membrane / Q000032:analysis; D002417:Cattle; D003094:Collagen / Q000032:analysis*; D007678:Kidney Glomerulus / Q000032:analysis*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid
chemical_list: D046911:Macromolecular Substances; D003094:Collagen