Stultz Collin M
Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA.
J Mol Biol. 2002 Jun 21;319(5):997-1003. doi: 10.1016/S0022-2836(02)00421-7.
Collagenases cleave all three chains of type III collagen at specific sites characterized by a Gly-Leu or a Gly-Ile bond that is upstream from an imino acid-poor region. Molecular dynamics trajectories were used to calculate the free energy of unfolding for collagen-like model peptides. The free energy profiles suggest that such imino-poor regions can adopt a low-energy, partially unfolded state where one of the peptide chains forms a solvent-exposed loop. The results are consistent with a model for collagenase cleavage where partial unfolding of imino-poor regions enables collagenases to gain access to their cleavage sites.
胶原酶在特定位点切割III型胶原的所有三条链，这些位点的特征是在富含亚氨基酸区域上游存在甘氨酸-亮氨酸或甘氨酸-异亮氨酸键。分子动力学轨迹用于计算类胶原模型肽的解折叠自由能。自由能分布图表明，此类富含亚氨基酸的区域可采用低能量、部分解折叠状态，其中一条肽链形成溶剂暴露环。这些结果与胶原酶切割模型一致，即富含亚氨基酸区域的部分解折叠使胶原酶能够接近其切割位点。
