Jaleel Zaroug, Zhou Shun, Martín-Moldes Zaira, Baugh Lauren M, Yeh Jonathan, Dinjaski Nina, Brown Laura T, Garb Jessica E, Kaplan David L
Department of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USA.
School of Medicine, Boston University, Boston, MA 02118, USA.
Materials (Basel). 2020 Aug 14;13(16):3596. doi: 10.3390/ma13163596.
The properties of native spider silk vary within and across species due to the presence of different genes containing conserved repetitive core domains encoding a variety of silk proteins. Previous studies seeking to understand the function and material properties of these domains focused primarily on the analysis of dragline silk proteins, MaSp1 and MaSp2. Our work seeks to broaden the mechanical properties of silk-based biomaterials by establishing two libraries containing genes from the repetitive core region of the native silk genome (Library A: genes , , , ; Library B: genes , , , ). The expressed and purified proteins were analyzed through Fourier Transform Infrared Spectrometry (FTIR). Some of these new proteins revealed a higher portion of β-sheet content in recombinant proteins produced from gene constructs containing a combination of / and / genes than recombinant proteins which consisted solely of dragline silk genes (Library A). A higher portion of β-turn and random coil content was identified in recombinant proteins from and genes (Library B). Mechanical characterization of selected proteins purified from Library A and Library B formed into films was assessed by Atomic Force Microscopy (AFM) and suggested Library A recombinant proteins had higher elastic moduli when compared to Library B recombinant proteins. Both libraries had higher elastic moduli when compared to native spider silk proteins. The preliminary approach demonstrated here suggests that repetitive core regions of the aforementioned genes can be used as building blocks for new silk-based biomaterials with varying mechanical properties.
由于存在不同的基因，这些基因包含保守的重复核心结构域，编码多种丝蛋白，天然蜘蛛丝的特性在物种内部和物种之间存在差异。先前旨在了解这些结构域的功能和材料特性的研究主要集中在对拖牵丝蛋白MaSp1和MaSp2的分析上。我们的工作旨在通过建立两个文库来拓宽基于丝的生物材料的机械性能，这两个文库包含来自天然丝基因组重复核心区域的基因（文库A：基因 、 、 、 ；文库B：基因 、 、 、 ）。通过傅里叶变换红外光谱（FTIR）对表达和纯化的蛋白质进行分析。与仅由拖牵丝基因组成的重组蛋白（文库A）相比，这些新蛋白中的一些在由包含 / 和 / 基因组合的基因构建体产生的重组蛋白中显示出更高比例的β-折叠含量。在来自 和 基因的重组蛋白（文库B）中鉴定出更高比例的β-转角和无规卷曲含量。通过原子力显微镜（AFM）对从文库A和文库B中纯化并制成薄膜的选定蛋白质进行机械表征，结果表明与文库B重组蛋白相比，文库A重组蛋白具有更高的弹性模量。与天然蜘蛛丝蛋白相比，两个文库都具有更高的弹性模量。此处展示的初步方法表明，上述基因的重复核心区域可作为具有不同机械性能的新型丝基生物材料的构建模块。
