Kajimura Daisuke, Takahashi Seiichiro, Yoshikawa Kiwamu, Hattori Shunji, Sado Yoshikazu, Imamura Yasutada, Hayashi Toshihiko
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan.
Biochem Biophys Res Commun. 2004 Jan 30;314(1):11-6. doi: 10.1016/j.bbrc.2003.12.061.
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.
我们之前的报告显示，培养的人类细胞在生理条件下会分泌非二硫键连接的非螺旋α1(IV)和α2(IV)链。在本报告中，我们表明非螺旋形式的α(IV)链对凝集素ABA（双孢蘑菇凝集素）有反应，而以三螺旋形式分泌的α(IV)链则没有。这些结果表明，ABA可用于区分IV型胶原多肽的两种构象异构体。用抗体偶联柱从人胎盘中分离出的α1(IV)链对ABA呈阳性反应，表明IV型胶原α1(IV)链的明胶形式在体内组织中产生并保留。从用无EDTA缓冲液纯化的非螺旋α1(IV)链含有包括NC1大小结构域在内的降解多肽并对活化的前MMP-9有明显抑制作用这一发现，讨论了明胶形式的可能意义。这是首次表明体内存在蛋白质明胶形式的报告。
