title: Non-helical type IV collagen polypeptides in human placenta.
abstract: Our previous reports showed that cultured human cells secrete non-disulfide-bonded non-helical alpha1(IV) and alpha2(IV) chains under physiological conditions. In the present report we show that the alpha(IV) chains in non-helical form were reactive to lectin ABA (Agaricus bisporus agglutinin), whereas the alpha(IV) chains secreted in triple-helical form were not. These results indicate that ABA could be used to distinguish the two conformational isomers of type IV collagen polypeptides. An alpha1(IV) chain isolated from human placenta with an antibody-coupled column showed a positive reaction to ABA, indicating that gelatin form of the type IV collagen alpha1(IV) chain is produced and retained in the tissue in vivo. A possible significance of the gelatin form is discussed from the finding that the non-helical alpha1(IV) chain purified with EDTA-free buffer contained degraded polypeptides including NC1-size domain and showed an apparent inhibition against activated pro-MMP-9. This is the first report to show that a gelatin form of protein exists in vivo.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kajimura
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Takahashi
authors.forename: Kiwamu
authors.initials: K
authors.lastname: Yoshikawa
authors.forename: Shunji
authors.initials: S
authors.lastname: Hattori
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Sado
authors.forename: Yasutada
authors.initials: Y
authors.lastname: Imamura
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Hayashi
mesh_terms: D002478:Cells, Cultured; D024141:Collagen Type IV / Q000737:chemistry* / Q000145:classification*; D004730:Endothelium, Vascular / Q000737:chemistry; D005347:Fibroblasts / Q000737:chemistry; D005920:Glomerular Mesangium / Q000737:chemistry; D006801:Humans; D037102:Lectins / Q000737:chemistry*; D008168:Lung / Q000737:chemistry / Q000196:embryology; D009131:Muscle, Smooth, Vascular / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D010920:Placenta / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D020033:Protein Isoforms / Q000737:chemistry; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D014470:Umbilical Cord / Q000098:blood supply / Q000737:chemistry
chemical_list: C041433:Agaricus lectins; D024141:Collagen Type IV; D037102:Lectins; D010455:Peptides; D020033:Protein Isoforms; D021122:Protein Subunits