中文摘要：

植物类型Ⅲ聚酮化合物合酶（PKS）催化合成多种植物次生代谢产物的基本分子骨架,参与植物体许多重要生物学功能的行使,一直是研究蛋白结构与功能关系、基于结构进行分子改造的重要模式分子家族。目前在蛋白质数据库（PDB）中有超过80个不同种属来源的类型Ⅲ PKS的三维结构被报道,其中包括了研究最为透彻的查尔酮合酶在内的7种酶的晶体结构,这些结构的发表对于阐明该类酶复杂多变的底物专一性、链延伸和不同的环化反应机制奠定了结构基础。三维空间结构解析以及基于定点突变的结构功能分析是进行酶工程、基因工程的基础。以下系统综述了植物类型Ⅲ PKS超家族晶体结构和功能的研究进展。

英文摘要：

Plant type Ⅲ polyketide synthase（PKS） generates backbones of a variety of plant secondary metabolites with diverse functions,and has long been models to elucidate the relationship between the three-dimensional structure and function.More than 80 type Ⅲ PKS crystal structures with different functions have been reported in Protein Data Bank,including the crystal structures of the well-studied Chalcone Synthase of plant type Ⅲ PKS,as well as the 6 other kinds of PKSs in the family,which are critical for understanding the structural basis for diverse starter molecule selectivity,polyketide chain length and the cyclization reaction.Structure-based analysis and site-directed mutagenesis are foundation for the investigation of enzyme engineering,genetic and metabolic engineering.This review summarized 7 plant-specific type Ⅲ PKS in the aspects of their crystal structures and functions.