Dunwell Jim M, Purvis Alan, Khuri Sawsan
The BioCentre, School of Plant Sciences, The University of Reading, Whiteknights, Reading, RG6 6AS, UK.
Phytochemistry. 2004 Jan;65(1):7-17. doi: 10.1016/j.phytochem.2003.08.016.
The cupin superfamily of proteins, named on the basis of a conserved beta-barrel fold ('cupa' is the Latin term for a small barrel), was originally discovered using a conserved motif found within germin and germin-like proteins from higher plants. Previous analysis of cupins had identified some 18 different functional classes that range from single-domain bacterial enzymes such as isomerases and epimerases involved in the modification of cell wall carbohydrates, through to two-domain bicupins such as the desiccation-tolerant seed storage globulins, and multidomain transcription factors including one linked to the nodulation response in legumes. Recent advances in comparative genomics, and the resolution of many more 3-D structures have now revealed that the largest subset of the cupin superfamily is the 2-oxyglutarate-Fe(2+) dependent dioxygenases. The substrates for this subclass of enzyme are many and varied and in total amount to probably 50-100 different biochemical reactions, including several involved in plant growth and development. Although the majority of enzymatic cupins contain iron as an active site metal, other members contain either copper, zinc, cobalt, nickel or manganese ions as a cofactor, with each cofactor allowing a different type of chemistry to occur within the conserved tertiary structure. This review discusses the range of structures and functions found in this most diverse of superfamilies.
“cupin超家族蛋白”是根据保守的β桶状折叠结构（“cupa”在拉丁语中意为小桶）命名的，最初是在高等植物的萌发素和类萌发素蛋白中发现的一个保守基序的基础上被发现的。此前对cupin蛋白的分析已确定了约18种不同的功能类别，范围从单结构域细菌酶，如参与细胞壁碳水化合物修饰的异构酶和差向异构酶，到双结构域双cupin蛋白，如耐干燥种子储存球蛋白，以及多结构域转录因子，包括一种与豆科植物结瘤反应相关的转录因子。比较基因组学的最新进展以及更多三维结构的解析现已表明，cupin超家族中最大的子集是2-氧代戊二酸-Fe(2+)依赖型双加氧酶。这类酶的底物多种多样，总共可能参与50-100种不同的生化反应，包括一些与植物生长和发育有关的反应。尽管大多数酶促cupin蛋白含有铁作为活性位点金属，但其他成员含有铜、锌、钴、镍或锰离子作为辅因子，每种辅因子在保守的三级结构中允许发生不同类型的化学反应。本综述讨论了这个最多样化的超家族中发现的结构和功能范围。
