Hasty K A, Wu H, Byrne M, Goldring M B, Seyer J M, Jaenisch R, Krane S M, Mainardi C L
Department of Anatomy and Neurobiology, University of Tennessee, Memphis 38104.
Matrix. 1993 May;13(3):181-6. doi: 10.1016/s0934-8832(11)80001-6.
Two members of the matrix metalloproteinase family which can cleave native types I, II and III triple helical collagens are collagenases from fibroblasts and neutrophils. These enzymes are the products of different genes which share structural motifs but are only 57% identical. In this study, we determined the site of cleavage in the alpha 1(I) chains and showed that the neutrophil collagenase acted at the same site as the fibroblast collagenase. We also used collagens as substrates which were generated by site-directed mutagenesis of the murine Col1a1 gene and found that the pattern of susceptibility to cleavage by purified neutrophil collagenase was indistinguishable from that previously described for the fibroblast collagenase. Collagens containing substitutions of Pro for Ile-776 (P1) were not cleaved; whereas those containing substitutions of Met for Ile-776 were cleaved. Type I collagen which contained alpha 1(I) chains in which there were double substitutions of Pro for Gln-774 (P2) and Ala-777 (P2') were also not cleaved. These type I collagens contained wild type alpha 2(I) chains as well as mutant alpha 1(I) chains in the mixed helical trimers; the alpha 2(I) chain in the trimers containing the resistant alpha 1(I) chains were also not cleaved by the neutrophil collagenase.
基质金属蛋白酶家族中有两种成员能够切割天然的I型、II型和III型三螺旋胶原，它们是来自成纤维细胞和中性粒细胞的胶原酶。这些酶是不同基因的产物，它们共享结构基序，但仅有57%的同源性。在本研究中，我们确定了α1(I)链的切割位点，并表明中性粒细胞胶原酶与成纤维细胞胶原酶的切割位点相同。我们还使用通过对小鼠Col1a1基因进行定点诱变产生的胶原作为底物，发现纯化的中性粒细胞胶原酶的切割敏感性模式与先前描述的成纤维细胞胶原酶的模式无法区分。含有将Ile-776（P1）替换为Pro的胶原未被切割；而含有将Ile-776替换为Met的胶原则被切割。含有α1(I)链且其中Gln-774（P2）和Ala-777（P2'）被Pro双重替换的I型胶原也未被切割。这些I型胶原在混合螺旋三聚体中包含野生型α2(I)链以及突变型α1(I)链；含有抗性α1(I)链的三聚体中的α2(I)链也未被中性粒细胞胶原酶切割。
