Orieshyna Anna, Puetzer Jennifer L, Amdursky Nadav
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia 23220, United States.
Biomacromolecules. 2023 Nov 13;24(11):4653-4662. doi: 10.1021/acs.biomac.3c00326. Epub 2023 Sep 1.
Collagen is one of the most studied proteins due to its fundamental role in creating fibrillar structures and supporting tissues in our bodies. Accordingly, collagen is also one of the most used proteins for making tissue-engineered scaffolds for various types of tissues. To date, the high abundance of hydroxyproline (Hyp) within collagen is commonly ascribed to the structure and stability of collagen. Here, we hypothesize a new role for the presence of Hyp within collagen, which is to support proton transport (PT) across collagen fibrils. For this purpose, we explore here three different collagen-based hydrogels: the first is prepared by the self-assembly of natural collagen fibrils, and the second and third are based on covalently linking between collagen via either a self-coupling method or with an additional cross-linker. Following the formation of the hydrogel, we introduce here a two-step reaction, involving (1) attaching methanesulfonyl to the -OH group of Hyp, followed by (2) removing the methanesulfonyl, thus reverting Hyp to proline (Pro). We explore the PT efficiency at each step of the reaction using electrical measurements and show that adding the methanesulfonyl group vastly enhances PT, while reverting Hyp to Pro significantly reduces PT efficiency (compared with the initial point) with different efficiencies for the various collagen-based hydrogels. The role of Hyp in supporting the PT can assist in our understanding of the physiological roles of collagen. Furthermore, the capacity to modulate conductivity across collagen is very important to the use of collagen in regenerative medicine.
胶原蛋白是研究最多的蛋白质之一，因为它在构建纤维状结构和支撑我们身体组织方面具有重要作用。因此，胶原蛋白也是用于制造各种组织工程支架的最常用蛋白质之一。迄今为止，胶原蛋白中高含量的羟脯氨酸（Hyp）通常被认为与胶原蛋白的结构和稳定性有关。在此，我们推测胶原蛋白中Hyp的存在具有一种新作用，即支持质子跨胶原蛋白纤维运输（PT）。为此，我们在此探索三种不同的基于胶原蛋白的水凝胶：第一种是通过天然胶原蛋白纤维的自组装制备的，第二种和第三种是基于胶原蛋白通过自偶联方法或使用额外的交联剂进行共价连接。在水凝胶形成后，我们在此引入两步反应，包括（1）将甲磺酰基连接到Hyp的 -OH基团上，然后（2）去除甲磺酰基，从而将Hyp还原为脯氨酸（Pro）。我们使用电学测量方法探索反应每个步骤的PT效率，并表明添加甲磺酰基极大地提高了PT效率，而将Hyp还原为Pro则显著降低了PT效率（与初始点相比），不同的基于胶原蛋白的水凝胶具有不同的效率。Hyp在支持PT方面的作用有助于我们理解胶原蛋白的生理作用。此外，调节跨胶原蛋白的电导率的能力对于胶原蛋白在再生医学中的应用非常重要。
