Zinc fingers can be loosely defined as protein domains containing one or more tetrahedrally-co-ordinated zinc ions whose role is to stabilise the structure rather than to be involved in enzymic chemistry; such zinc ions are often referred to as “structural zincs”. Although structural zincs can occur in proteins of any size, they assume particular significance for very small protein domains, where they are often essential for maintaining a folded state. Such small structures, that sometimes have only marginal stability, can present particular difficulties in terms of sample preparation, handling and structure determination, and early on they gained a reputation for being resistant to crystallisation. As a result, NMR has played a more prominent role in structural studies of zinc finger proteins than it has for many other types of proteins. This review will present an overview of the particular issues that arise for structure determination of zinc fingers by NMR, and ways in which these may be addressed.

锌指可以宽泛地定义为包含一个或多个四面体配位锌离子的蛋白质结构域，其作用是稳定结构而不是参与酶化学；这种锌离子通常被称为“结构锌”。尽管结构锌可以存在于任何大小的蛋白质中，但它们对非常小的蛋白质结构域具有特殊意义，在这些结构域中它们通常对于维持折叠状态至关重要。这种有时只有边缘稳定性的小结构在样品制备、处理和结构确定方面可能会带来特别的困难，并且在早期它们就以抗结晶而闻名。因此，与许多其他类型的蛋白质相比，NMR 在锌指蛋白的结构研究中发挥了更突出的作用。