- 作者: Wei-Hsuan Yu, Po-Tsang Huang, Kuo-Long Lou, Shuan-Su C. Yu and Chen Lin
- 作者服務機構: Institute of Biochemistry and Molecular Biology, National Taiwan University, College of Medicine, Taiwan, R.O.C.
- 中文摘要: --
- 英文摘要: The X-ray structures of the four subfamilies of the metzincins have been solved; in particular, the structures of a number of MMPs, including matrilysin, have been solved. These metalloproteases have a catalytic domain consisting of a twisted five-stranded sheet and three long helices (A, B and C). The catalytic zinc is at the bottom of the cleft and is ligated by three His residues in the consensus sequence motif, HEXXHXXGXXH, which is located in helix B and part of the adjacent Met turn region. We have expressed a 60-residue truncated form of matrilysin which retains only the helix B-Met turn-helix C region and deletes helix A and the five-stranded sheet which form the upper portion of the active cleft. This is only 1/4 of the full catalytic domain. This minimal 6 kDa matrilysin has been refolded and shown to have proteolytic activity in the Mca-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2 peptide assay. Triton X-100 and heparin are important factors in the refolding environment for this mini-enzyme matrilysin. This minienzyme has the proteolytic activity towards peptide substrate, but the hexomer and octmer of the mini MMP-7 complex demonstrates the CM-transferrin proteolytic activities in zymographic analysis. but peptide digestion is inhibited by SC44463 and BB94, specific MMP inhibitors. TIMP-1 gives partial inhibition. Interestingly, the mini MMP-7 can be processed by autolysis and producing ~ 6~7 kDa fragments. Thus, many of the functions of the enzyme are retained indicating that the helix B-Met loop-helix C is the minimal functional "domain" found to date for the matrixin family.
- 中文關鍵字: --
- 英文關鍵字: Matrilysin, Zinc-dependent proteolytic domain, Catalytic zinc binding domain, Helix-loophelix, SC44463