AMINO ACIDS CHIMERAS--MODELING COENZYME CATALYSIS

氨基酸嵌合体——模拟辅酶催化

• 批准号: 2192369
• 负责人: Barbara Imperiali
• 金额: $ 17.35万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 1999-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2192369
• 关键词: catalyst; chemical models; chemical structure function; chimeric proteins; coenzyme analog; cofactor; decarboxylases; enzyme model; nicotinamide adenine dinucleotide; peptide chemical synthesis; stereochemistry; synthetic peptide; thiamine pyrophosphate; transamination

Coenzymes play a critical role in many enzyme catalyzed processes by providing functionality not accessible in the naturally encoded amino acids. In this research, the potential utility of a series of catalytically competent coenzyme amino acid chimeras in protein design will be explored. These residues incorporate the core functionality of the coenzymes pyridoxal/pyridoxamine phosphate, nicotinamide adenine dinucleotide and thiamin diphosphate as integral constituents of alpha- amino acid constructs. In these forms, the coenzyme functionalities can be incorporated into a polypeptide at any position within the primary sequence via solid phase peptide synthesis. The long term goals of this research are to develop complex an appropriate peptidyl architecture to host the functional coenzyme moieties. In addressing these challenges knowledge will be gained on the manipulation of the peptide architecture for the construction of new catalysts. The specific aims of this proposal center on the development of three new catalytic systems. (l) An alpha-amino acid/alpha-keto acid transaminase that incorporates a pyridoxamine amino acid chimera, (2) A thiazolium dependent alpha-keto acid decarboxylase and (3) A nicotinamide dependent system for the stereospecific reduction of unactivated ketones that employs divalent zinc for carbonyl activation. Each amino acid will be built into a polypeptide architecture of de novo design. The motifs that will be employed include alpha-helical bundles and beta-beta-alpha supersecondary structural elements. The complexity of these constructs will allow for significant structural variation necessary for developing the reactivity and selectivity that is the hallmark of enzyme catalysis. This research will provide important insight into the interplay between peptide structure and function in coenzyme catalysis. Studies of this kind may lead to the evolution of selective new catalysts for key organic transformations.

辅酶在许多酶催化过程中起着至关重要的作用 在自然编码的氨基中提供无法访问的功能 酸。在这项研究中，一系列的潜在效用 蛋白质设计中的催化能干辅酶氨基酸嵌合体 将被探索。这些残基包含了 辅酶吡啶毒素/吡id胺磷酸盐，烟酰胺腺嘌呤 二核苷酸和硫胺二磷酸作为α-的积分成分 氨基酸构建体。在这些形式中，辅酶功能可以是 在初级的任何位置纳入多肽 通过固相肽合成的序列。 这项研究的长期目标是发展复杂 肽基体系结构可容纳功能性辅酶部分。在 解决这些挑战的知识将得到解决 用于建造新催化剂的肽架构。 该提案中心的特定目的是开发三个新的 催化系统。 （L）α-氨基酸/α-酮酸转氨酶 结合了吡id胺氨基酸嵌合体，（2）噻唑烷 依赖性α-酮酸脱羧酶和（3）烟酰胺依赖性 立体特定降低未活化酮的系统 采用二价锌进行羰基活化。每个氨基酸将是 内置在从头设计的多肽架构中。主题 将使用包括α-螺旋束和β-beta-alpha 高等结构元素。这些结构的复杂性 将允许开发必要的重大结构变化 是酶催化的标志的反应性和选择性。 这项研究将为对之间的相互作用提供重要的见解 肽结构和辅酶催化中的功能。这类研究 可能导致关键有机过程的选择性新催化剂的演变 转型。