Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Centre, Uppsala University, SE-75123 Uppsala, Sweden.
J Biol Chem. 2012 Aug 3;287(32):27001-6. doi: 10.1074/jbc.R111.300129. Epub 2012 Jun 14.
Circular proteins, defined as head-to-tail cyclized polypeptides originating from ribosomal synthesis, represent a novel class of natural products attracting increasing interest. From a scientific point of view, these compounds raise questions of where and why they occur in nature and how they are formed. From a rational point of view, these proteins and their structural concept may be exploited for crop protection and novel pharmaceuticals. Here, we review the current knowledge of three protein families: cyclotides and circular sunflower trypsin inhibitors from the kingdom of plants and the Amanita toxins from fungi. A particular emphasis is placed on their biological origin, structure, and activity. In addition, the opportunity for discovery of novel circular proteins and recent insights into their mechanism of action are discussed.
环状蛋白，定义为源自核糖体合成的头尾环化多肽，代表了一类新兴的天然产物，引起了越来越多的关注。从科学的角度来看，这些化合物提出了它们在自然界中出现的位置、原因以及它们是如何形成的问题。从理性的角度来看，这些蛋白质及其结构概念可能被用于作物保护和新型药物。在这里，我们回顾了三种蛋白质家族的最新知识：来自植物王国的环肽和向日葵胰蛋白酶抑制剂，以及真菌中的鹅膏蕈毒素。特别强调了它们的生物起源、结构和活性。此外，还讨论了发现新型环状蛋白的机会以及对其作用机制的最新见解。
