Plant type Ⅲ polyketide synthases (PKSs), the pivotal enzymes in the biosynthesis of polyketides, produce backbones of many structurally diverse and functionally different polyketides. So far, a variety of functionally diverse plant type Ⅲ PKSs have been cloned and identified from plant origin. Site-directed mutagenesis is a useful technique to study the complex relationship between protein structure and function. This review summarized advances in the structure-function relation of plant type Ⅲ polyketide synthases by site-directed mutagenesis in recent years, including the modification of the amino acid residues influencing enzyme architectures (such as controlling the specificity of starter substrates, the number of condensation reactions, and the cyclization reactions of the intermediate product). This review provides information to study the structure-function relation of plant type Ⅲ polyketide synthases.
植物Ⅲ型聚酮合酶 (Polyketide synthases，PKSs) 催化形成一系列结构迥异、生理活性不同的聚酮类化合物的基本骨架结构，是聚酮类化合物生物合成途径的关键酶。目前已从植物中克隆和鉴定了多种功能不同的Ⅲ型PKSs。定点突变技术是研究蛋白质结构与功能之间复杂关系的重要方法。文中综述了近年来基于定点突变的植物Ⅲ型PKSs 结构与功能关系的研究进展，包括利用定点突变技术修饰各种可能影响植物Ⅲ型PKSs 结构的氨基酸残基，来研究其对功能的影响 (如控制起始底物的特异性、缩合反应次数以及中间产物环化方式)，以期为植物Ⅲ型PKSs 结构与功能关系的研究提供参考。.
Keywords: plant type Ⅲ polyketide synthases; polyketides; site-directed mutagenesis; structure and function.