Elucidating Water-Ionic Liquid-Enzyme Mixtures Interactions for Enhanced Deconstruction of Cellulosic Biomass

主要研究者：Maupin，ChristopherProposal Number：1337044机构：科罗拉多矿业学院标题：阐明水离子液体酶混合物的相互作用，以增强纤维素生物质的解构纤维素工程增强系统的解构是必不可少的生物质生产液体燃料和其他增值化学品的成本效益的利用。不幸的是，结晶纤维素底物的不溶性和由多相催化引起的所产生的限制导致不适合大规模工业过程的高反应时间。任务特异性离子液体（IL）是一个有前途的？绿色？超溶剂，其能够快速溶解结晶纤维素生物质，同时还保持纤维素酶活性，从而提供了一种有希望的途径，以一步均相降解纤维素生物质。然而，仍然有很多关于了解潜在的IL-酶的相互作用影响酶的结构，活性和stability.In这个计算和实验相结合的项目，我们提出了一个双管齐下的方法来评估两个纤维素酶的三个IL之间的相互作用。所研究的纤维素酶在IL-H2O混合物中显示出不同程度的活性，允许鉴定功能性所需的特定酶特征，而不同的IL-H2O混合物能够鉴定有利地影响酶功能性的特定IL特征。通过以下目标来鉴定导致酶功能和活性改变的特异性IL-酶相互作用：（1）IL-H2O-酶系统的MD模拟。这些模拟将揭示特定的IL-酶相互作用及其对酶的动力学波动和整体结构的影响。（2）对IL-H_2O-酶和IL-H_2O-纤维素低聚物体系进行热力学积分计算。这些计算探索了IL进入纤维素酶活性位点的能力，并阐明了竞争溶剂化能的作用。（3）对IL-H_2 O-酶体系进行CpHMD模拟。这些模拟将揭示IL混合物对活性位点中关键残基的pKa的影响。（4）进行IL-H_2 O-酶降解纤维素的动力学分析。这些实验将揭示IL-H2O混合物对所观察到的酶活性的影响。计算和实验研究将提供对IL-酶相互作用的分子水平的理解，并且对结构、动力学波动、pKa值和溶剂化的影响将阐明溶剂环境如何影响酶和其他与工业过程相关的大分子系统的功能。此外，对促进结构稳定性和活性的酶和IL性质的评估将使得能够使用合理的设计来为广泛的行业创建定制的酶和IL。与研究紧密结合的是跨多个教育层次的下一代科学家和工程师的教育。参与STEM领域代表性不足的群体是通过与马丁·路德·金的大学预科学生（REPS）外展计划的研究经验来完成的。丹佛的一所高中。除了纳入美国科学促进会太平洋分部区域会议和博伊西州立大学（主要是本科院校）的计算讲习班之外，研究工作还将通过研究文章、区域和国家会议广泛传播。

PI: Maupin, ChristopherProposal Number: 1337044Institution: Colorado School of MinesTitle: Elucidating Water-Ionic Liquid-Enzyme Mixtures Interactions for Enhanced Deconstruction of Cellulosic BiomassEngineering enhanced systems for the deconstruction of cellulose is essential to the cost-effective utilization of biomass for production of liquid fuels and other value added chemicals. Unfortunately, the insolubility of the crystalline cellulose substrate and resulting limitations incurred by heterogeneous catalysis leads to high reaction times that are not suitable for large scale industrial processes. Task specific ionic liquids (IL) are a promising ?green? super solvent that enable the rapid dissolution of crystalline cellulosic biomass while also retaining cellulase enzyme activity thereby providing a promising route to a single step, homogeneous phase degradation of cellulosic biomass. However, much remains in regards to understanding the underlying IL-enzyme interactions affecting enzyme structure, activity, and stability.In this combined computational and experimental project we propose a two pronged approach to evaluate the interactions between three ILs on two cellulase enzymes. The cellulase enzymes being studied have shown varying degrees of activity in IL-H2O mixtures, allowing for the identification of specific enzyme features necessary for functionality while the different IL-H2O mixtures enable the identification of specific IL features that favorably affect enzyme functionality. The identification of specific IL-enzyme interactions leading to altered enzyme functionality and activity will be accomplished through the following objectives: (1) MD simulations on IL-H2O-enzyme systems. These simulations will reveal specific IL-enzyme interactions and their impact on dynamic fluctuations and the overall structure of the enzyme, (2) Conduct Thermodynamic Integration calculations on IL-H2O-enzyme and IL-H2O-cellulose oligomer systems. These calculations probe the ability of the IL to enter the active site of cellulose enzymes and illuminate the role of competing solvation energies, (3) Conduct CpHMD simulations on IL-H2O-enzyme systems. These simulations will reveal the impact of IL mixtures on the pKa of critical residues in the active site, and (4) Conduct kinetic analysis of IL-H2O-enzyme degradation of cellulose. These experiments will reveal the impact of IL-H2O mixtures on the observed enzyme activity.The computational and experimental studies will provide an increased molecular-level understanding of the IL-enzyme interactions and the resulting effect on structure, dynamical fluctuations, pKa values, and solvation will elucidate how the solvent environment impacts the functionality of enzymes and other macromolecule systems relevant to industrial processes. In addition, evaluation of the enzyme and IL properties that facilitate structural stability and activity will enable the use of rational design to create tailored enzymes and ILs for a wide range of industries. Closely integrated with the research is the education of the next generation of scientists and engineers across multiple education levels. Engaging underrepresented groups in STEM fields is accomplished through the Research Experience for Pre-Collegiate Students (REPS) outreach program with Martin Luther King Jr. Early ollege, a Denver high school. The research effort will be broadly disseminated through research articles, regional and national meetings, in addition to the incorporation into computational workshops at the regional AAAS Pacific Division meetings and Boise State University, a primarily undergraduate institution.