Catalytic Hydrogels from Bifunctional Enzymatic Building Blocks

该奖项由哥伦比亚大学材料研究部的生物材料项目资助，该项目正在研究利用分子工程创造新型双功能酶，这种酶可以自组装成水凝胶，并支持凝胶内代谢途径，通过两步氧化甲醇生成甲酸。合理设计的α -螺旋附属物将与马肝脏乙醇脱氢酶同型二聚体酶和人肝脏线粒体醛脱氢酶同型四聚体酶基因融合。将评估这些突变对酶性能的影响，然后将酶组合形成混合的自组装水凝胶，将甲醇氧化成甲酸，同时从反应所需的辅助因子NAD+产生NADH。这将是首次证明自组装生物活性生物材料可以支持简单的凝胶内代谢网络的原理。这种材料可以应用于电极，并在使用甲醇作为燃料源的酶生物燃料电池中用作阳极。蛋白质工程已被用于改善球形蛋白，如酶和结构蛋白，如弹性蛋白样肽。该研究项目是设计和创造具有球状和结构域的新蛋白质，以形成具有生物活性的生物材料。研究人员早期的研究已经对蛋白质进行了修饰，使其能够自组装成酶凝胶，而在这项提议中，研究人员将创造一种包含两种活性酶的新材料，这两种酶可以一起起作用，形成一个简单的代谢途径。酶能先将甲醇氧化成甲醛，然后甲醛再被氧化成甲酸。每一步都将产生NADH，它可以用于发电形式，如酶生物燃料电池。创造既具有有用的酶和材料性质的新型蛋白质结构是蛋白质工程领域的一个新领域，这种方法将在设计和构建新的生物电催化装置（如酶生物燃料电池和生物传感器）方面非常有用。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5) This award by the Biomaterials program in the Division of Materials Research to Columbia University is study the use of molecular engineering to create novel bifunctional enzymes that can self-assemble into hydrogels and support an intra-gel metabolic pathway that can oxidize methanol through two steps to formic acid. Rationally designed alpha-helical appendages will be genetically fused to the horse liver alcohol dehydrogenase homodimer enzyme and to the human liver mitochondrial aldehyde dehydrogenase homotetramer enzyme. The effects of these mutations on the performance of the enzymes will be assessed, and then the enzymes will be combined to form mixed self-assembling hydrogels that will oxidize methanol to formic acid while concomitantly producing NADH from NAD+ a cofactor required for the reaction. This will be the first proof of principle of a self-assembling bioactive biomaterial that can support a simple intra-gel metabolic network. This material could be applied to an electrode and used as an anode in an enzymatic biofuel cell using methanol as a fuel source.Protein engineering has been used to improve globular proteins such as enzymes, and structural proteins such as the elastin-like peptides. This research project is designing and creating new proteins with both globular and structural domains to form bioactive biomaterials. Earlier studies by the researcher already modified proteins to self-assemble into enzymatic hydrogels, and in this proposal the investigators will create a new material that contains two active enzymes which can function together to form a simple metabolic pathway. The enzymes will be able to oxidize methanol first to formaldehyde and then the formaldehyde will be oxidized to formic acid. Each step will generate NADH which can be used in a power generating format such as an enzymatic biofuel cell. The creation of novel protein constructs with both useful enzymatic and materials properties is a new area in the field of protein engineering, and this approach will be very useful in the design and construction of new bioelectrocatalytic devices such as enzymatic biofuel cells and biosensors.