新型微生物谷氨酰胺转氨酶的挖掘及其酰基供体特异性机制的研究

微生物谷氨酰胺转氨酶(TGase)能催化蛋白质中谷氨酰胺残基(酰基供体)转移至赖氨酸残基或其它氨基化合物(酰基受体)，形成的酰胺共价键使蛋白质交联或与氨基化合物连接。研究表明，TGase只能以具有特定相邻氨基酸残基的谷氨酰胺为酰基供体，有限的酰基供体识别范围成为其在制药、纺织及皮革等领域应用的主要障碍。为拓宽TGase酰基供体谱，实现对酰基供体特异性的有效调控，申请人拟开展如下研究：(1)通过生物信息学方法从基因数据库中筛选代表性微生物TGase，构建与已报道TGase具有不同酰基供体特异性的酶库；(2)分析新型微生物TGase与其酰基供体的相互作用，揭示不同TGase酰基供体结合方式的差异；(3)对影响酶-酰基供体结合位点的关键区域进行改造，调控TGase酰基供体特异性。研究结果将有助于人们加深对酰基转移酶类催化机制的认识，同时为TGase改造和高效应用提供理论支撑。

Microbial transglutaminase (TGase) can catalyze the transfer of glutamine residues (acyl donors) in proteins to lysine residues or other amino compounds (acyl receptors), forming an amide covalent bond to crosslink or connect proteins with amino compounds. A number of studies have indicated that TGase could only recognized those Glutamines with specific flanking residues as its acyl donors, and the limited scope of acyl donor recognition has become the main obstacle in the application of TGase in pharmaceutical, textile and leather indutries. In order to broaden the acyl donor spectrum of TGase and effectively regulate the acyl donor specificity, we intend to carry out the following researches: (1) Select the representative microorganism TGase from the gene database through the bioinformatic methods, and construct the enzyme library with acyl donor specificities different from the reported TGase; (2) Analyze the interactions between the novel microbial TGase and its acyl donor and reveal the difference in acyl donor-docking model among different TGases; (3) The key regions of enzyme that affect the acyl donor binding were modified to regulate the acyl donor specificity of TGase. The research results will help people to understand the catalytic mechanism of acyltransferase, and provide theoretical support for the efficient modification and application of TGase.