Presidential Young Investigator Award

这项研究涉及利用生物聚合物的生物降解性、手性和空间有序性来构建重要的新材料。细菌聚酯、纤维素和溶菌酶已被选择用于这项工作。由细菌发酵而来的聚羟基丁酸酯-羟基戊酸酯(PHBVc)被用来获得具有相同组成但在晶格结构、结晶完整性、球晶尺寸和结晶度百分比上不同的材料。通过对手性纯的正构烷基内酯进行开环聚合，合成了细菌聚酯的合成类似物。PHBV正在与其他聚合物混合，以形成不同的形态。然后将使用不同的生物环境来研究这些样品的微生物降解性。通过这种方式，将建立聚合物结构、形态和降解性之间的基本关系。纤维素衍生物将被用来形成液晶聚合物材料，其中胆甾相的沥青将对外部信号高度敏感。通过合成具有光和电响应性基团的纤维素衍生物，聚合物设计、施加的外部信号和材料的光学旋转性能之间的关系将被建立。这一概念将扩展到其他基于手性生物聚合物的系统，以探索链动力学对响应时间的影响。在蛋白质溶菌酶的选择性位置插入光响应基团和电响应基团将被用于启动对酶构象调节的研究，从而启动活性的研究。这项工作的目标是探索允许酶基本上被打开和关闭的方法，以响应改变蛋白质催化位置的空间排列的外部信号。这些蛋白质可能为光和电信号的传递提供新的途径。

This research involves exploiting the biodegradability, chirality, and spatial order of biopolymers for the construction of important new materials. The bacterial polyesters, cellulose, and lysozyme have been selected for this work. Poly(hydroxybutyrate-co-hydroxyvalerate), PHBV, derived from bacterial fermentation is being used to obtain materials which have identical compositions but differ in the crystalline lattice structure, crystalline perfection, spherulite size, and percent crystallinity. Synthetic analogues of bacterial polyesters are being synthesized by carrying out a ring-opening polymerization of enantiomerically pure n-alkyl lactones. PHBV is being blended with other polymers to develop different morphologies. The microbial degradability of these samples will then be studied using variable biological environments. In this way, fundamental relationships between polymer structure, morphology, and degradability will be established. Cellulose derivatives will be used to form liquid crystalline polymeric materials where the cholesteric pitch will be highly sensitive to external signals. By synthesizing cellulose derivatives which have photo- and electroresponsive groups attached at controlled sites along the chain, relationships between polymer design, the aplied external signal, and the optical rotatory properties of the material will be established. This concept will be extended to other chiral biopolymer based systems to explore the effects of chain dynamics on response time. The insertion of photo- and electroresponsive groups at selective sites of the protein lysozyme will be used to initiate research into the modulation of enzyme conformation, and therefore activity. The goal of this work is to explore methods which allow enzymes to essentially be turned on and off in response to external signals which alter the spatial arrangements at protein catalytic sites. These proteins may provide novel routes for the transmission of light and electrical signals.