Romanic A M, Adachi E, Hojima Y, Engel J, Prockop D J
Department of Biochemistry and Molecular Biology, Jefferson Institute of Molecular Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
J Biol Chem. 1992 Nov 5;267(31):22265-71.
Previous observations established that pNcollagen III copolymerized with collagen I and decreased the diameter of the fibrils formed (Romanic, A.M., Adachi, E., Kadler, K.E., Hojima, Y., and Prockop, D.J. (1991) J. Biol. Chem. 266, 12703-12709). Here, procollagen I alone or mixtures of procollagen I and pCcollagen I were incubated with procollagen C-proteinase to generate pNcollagen I or mixtures of pNcollagen I and collagen I. The results confirmed previous reports that pNcollagen I assembles into sheet-like structures. They also demonstrated that polymerization of pNcollagen I exhibits a lag period and propagation phase similar to those seen with other protein self-assembly systems. In addition, the results demonstrated that pNcollagen I formed true copolymers with collagen I in that the presence of pNcollagen I increased the lag time, decreased the propagation rate, and increased the concentration of collagen I in solution at equilibrium. Copolymerization of pNcollagen I with collagen I, however, differed in two features from copolymerization of pNcollagen III with collagen I. One was that, in confirmation of previous work, copolymerization of pNcollagen I with collagen I markedly altered the circularity of the fibrils formed. The second difference was that the copolymerization increased the concentration in solution at equilibrium of pNcollagen I whereas copolymerization with collagen I was previously shown to decrease the concentration in solution of pNcollagen III. The increase in concentration in solution of pNcollagen I was explicable either by the assembly of soluble oligomers of pNcollagen I and collagen I, or by subtle changes in the activities of pNcollagen I and collagen I in the solid-phase. Comparison with previous data with pNcollagen III indicated that although pNcollagen I and pNcollagen III copolymerize with collagen I, there are marked differences in the two kinds of copolymers.
先前的观察结果表明，Ⅲ型前胶原与Ⅰ型胶原共聚，并减小了所形成原纤维的直径（罗曼尼克，A.M.，安达千绘，E.，卡德勒，K.E.，保岛洋，Y.，和普罗科普，D.J.（1991年）《生物化学杂志》266卷，12703 - 12709页）。在此，单独的Ⅰ型前胶原或Ⅰ型前胶原与Ⅲ型前胶原的混合物与前胶原C蛋白酶一起孵育，以生成Ⅰ型前胶原或Ⅰ型前胶原与Ⅰ型胶原的混合物。结果证实了先前的报道，即Ⅰ型前胶原组装成片状结构。结果还表明，Ⅰ型前胶原的聚合表现出与其他蛋白质自组装系统类似的延迟期和增长期。此外，结果表明，Ⅰ型前胶原与Ⅰ型胶原形成了真正的共聚物，因为Ⅰ型前胶原的存在增加了延迟时间，降低了增长速率，并增加了平衡时溶液中Ⅰ型胶原的浓度。然而，Ⅰ型前胶原与Ⅰ型胶原共聚在两个方面不同于Ⅲ型前胶原与Ⅰ型胶原的共聚。一是，如先前工作所证实的，Ⅰ型前胶原与Ⅰ型胶原共聚显著改变了所形成原纤维的圆度。第二个差异是，共聚增加了平衡时溶液中Ⅰ型前胶原的浓度，而先前表明与Ⅰ型胶原共聚会降低溶液中Ⅲ型前胶原的浓度。Ⅰ型前胶原溶液浓度的增加，要么是由于Ⅰ型前胶原和Ⅰ型胶原的可溶性寡聚物的组装，要么是由于固相中的Ⅰ型前胶原和Ⅰ型胶原的活性发生了细微变化。与先前关于Ⅲ型前胶原的数据比较表明，尽管Ⅰ型前胶原和Ⅲ型前胶原都与Ⅰ型胶原共聚，但这两种共聚物存在显著差异。
