Circular proteins from plants and fungi.
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.
Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Centre, Uppsala University, SE-75123 Uppsala, Sweden. ulf.goransson@fkog.uu.se
Ulf
U
Göransson
Robert
R
Burman
Sunithi
S
Gunasekera
Adam A
AA
Strömstedt
K Johan
KJ
Rosengren
D000595:Amino Acid Sequence; D005656:Fungal Proteins / Q000737:chemistry / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification*; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification*; D017386:Sequence Homology, Amino Acid
D005656:Fungal Proteins; D010456:Peptides, Cyclic; D010940:Plant Proteins