Protein fold class, typically <100 amino acids long
Small proteins are a diverse fold class of proteins (usually <100 amino acids long).[1][2][3] Their tertiary structure is usually maintained by disulphide bridges,[4]metal ligands,[5] and or cofactors such as heme. Some small proteins serve important regulatory functions by direct interaction with certain enzymes and are therefore also an interesting tool for biotechnological applications in microorganisms. [6]