Exploration of the denaturation and refolding of natural collagen is important for the application of collagen and its denatured products. In this study, using urea as a denaturant, we prepared a denatured natural collagen product and analyzed its structural changes. The denaturation treatment severely destroyed the triple helix conformation of collagen, but had no significant effect on the primary structure of its a chains or the covalent cross-linking between a chains. Next, we observed the refolding behavior of the denatured collagen by removing urea through dialysis. We found that the denatured collagen products from different sources (grass carp skin, bovine tendon) all showed a reconstruction of the triple helix conformation up to 60–75% of the value of natural collagen during the refolding process. The telopeptide did not significantly promote triple helix reconstruction. In conclusion, the reconstruction of the a chains did not perfectly occur in a “head-to-head, tail-to-tail” manner in refolded collagen, as each a chain was participating in the reconstruction of multiple triple helix domains. The refolded collagen still had weak self-assembly ability and formed a unique network-like structure containing small interlaced and closely combined fibers, which shows favorable cell compatibility and potential applications.

探索天然胶原蛋白的变性和重折叠对于胶原蛋白及其变性产品的应用具有重要意义。在这项研究中，我们使用尿素作为变性剂，制备了一种变性的天然胶原蛋白产品并分析了其结构变化。变性处理严重破坏了胶原的三螺旋构象，但对其a链的一级结构或a链之间的共价交联没有显着影响。接下来，我们通过透析去除尿素来观察变性胶原蛋白的重折叠行为。我们发现来自不同来源（草鱼皮、牛腱）的变性胶原蛋白产品在重折叠过程中都显示出高达天然胶原蛋白价值的 60-75% 的三螺旋构象的重建。端肽没有显着促进三螺旋重建。总之，在重折叠的胶原蛋白中，a 链的重建并没有完全以“头对头、尾对尾”的方式发生，因为每个 a 链都参与了多个三螺旋结构域的重建。重折叠的胶原蛋白仍具有较弱的自组装能力，形成了独特的网状结构，其中含有细小的交织紧密结合的纤维，显示出良好的细胞相容性和潜在的应用前景。