Designing Spider Silk Proteins as Novel Biomaterials

描述(由申请人提供)： 蜘蛛丝已经进化了4.5亿多年，其抗拉强度比钢更大，弹性比尼龙更大。许多蜘蛛丝基因已经被克隆和测序，揭示了特定的氨基酸基序，这些基序已经被保存了超过1.25亿年。在下一步从蜘蛛丝中产生生物基材料的关键要素将是从当前的描述性数据转移到预测性知识。还没有人系统地改变蜘蛛丝蛋白中的序列基序，并确定这如何影响所产生的纤维的机械性能。这些实验将提供预测性知识，从而能够为每种不同的医疗应用设计具有非常特定的弹性和强度属性的材料。这项提议旨在检验三个基本假设和工程概念。1)从蜘蛛丝组装成蛋白质的氨基酸序列基序可以用来创造自组装的弹性材料。2)材料的弹性将与弹性图案的数量成正比。3)改变弹性区域的顺序会改变弹性(杨氏)模数。这里描述了一个简短的工作计划。1)基于自然产生的蜘蛛丝序列和在合适的宿主系统中表达的编码蛋白质，基因的弹性模体的数量和序列将发生变化；2)这些不同的蛋白质中的每一种都将用于制造纤维和薄膜。3)对薄膜和纤维进行机械性能测试。要测量的性质将是抗拉强度、弹性(可恢复伸长率)、总伸长率、断裂能和弹性模数。4)蛋白质在溶液、薄膜和纤维中的结构将通过傅里叶变换红外光谱(FTIR)、圆二色谱(CD)和固体核磁共振确定。5)将弹性和弹性模量数据与每种类型基元的数量和顺序相关联，以产生对弹性和其他材料性质的预测算法。这个项目之所以意义重大，有几个原因。首先，它将提供对蜘蛛丝蛋白中弹性和拉伸强度的基本了解，具体地说，它将揭示是什么控制着弹性和弹性模数的量，以及这两个因素是否可以以可预测的方式变化。其次，该项目将提高我们将蜘蛛丝用作生物材料的能力。如果我们的假设是正确的，我们将学习如何通过控制蛋白质序列来控制弹性和其他材料属性。蜘蛛丝的可能应用范围从人造韧带和肌腱到烧伤绷带，再到多种用途的复合材料。

DESCRIPTION (provided by applicant): Spider silk, which has been evolving for over 450 million years, has a tensile strength greater than steel and elasticity greater than nylon. A number of spider silk genes have been cloned and sequenced revealing specific amino acid motifs that have been conserved for over 125 million years. The key element in taking the next step toward generating biobased materials from spider silks will be to move from the current descriptive data to predictive knowledge. No one has systematically varied the sequence motifs in the spider silk proteins and determined how this influences the mechanical properties of the resulting fibers. These experiments will provide the predictive knowledge enabling the design of materials with very specific elastic and strength properties for each different medical application. This proposal is designed to test three basic hypotheses and engineering concepts. 1) Amino acid sequence motifs from spider silk assembled into a protein can be used to create self-assembling elastic materials. 2) The elasticity of the materials will be proportional to the number of elastic motifs. 3) Varying the sequence of the elastic regions will vary elastic (Young's) modulus. A brief work plan is described here. 1) Genes will be constructed with variations in the number and sequence of elastic motifs, based on naturally occurring spider silk sequences and the encoded proteins expressed in a suitable host system, 2) Each of these different proteins will be used to make both fibers and thin films. 3) The films and fibers will be tested for their mechanical properties. The properties to be measured will be tensile strength, elasticity (recoverable elongation), total elongation, energy to break and elastic modulus, 4) The structure of the protein in solution, films and fibers will be determined by Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) and by solid state NMR. 5) The elasticity and elastic modulus data will be correlated with the number and sequence of each type of motif to produce a prediction algorithm for elastic and other materials properties. This project is highly significant for several reasons. First it will provide a basic understanding of elasticity and tensile strength in spider silk proteins, Specifically, it will reveal what controls the amount of elasticity and elastic modulus and if these two factors can be varied in a predictable way. Second this project will advance our ability to use spider silk as a biomaterial. If our hypotheses are correct we will learn how to control the elasticity and other materials properties by controlling the protein sequence. Possible applications of spider silk range from artificial ligaments and tendons to bandages for burns to composite materials for multiple applications.