Cys2His2tyyppisessä

Cys2His2tyyppisessä refers to a common structural motif found in DNA-binding proteins. This motif is characterized by a specific arrangement of cysteine and histidine amino acid residues that coordinate a zinc ion, which is essential for the protein's ability to bind to DNA. The "Cys2His2" part of the name indicates the presence of two cysteine residues and two histidine residues within a particular loop or domain of the protein. These residues are typically positioned in a way that forms a tetrahedral structure around the zinc ion. The term "tyyppisessä" is Finnish for "typical" or "in the type of," implying that this is a representative or standard example of such a zinc finger domain. Proteins containing Cys2His2 zinc fingers play crucial roles in gene regulation, acting as transcription factors that can either activate or repress the expression of specific genes by binding to particular DNA sequences. The specific DNA sequence recognized by a Cys2His2 zinc finger protein is determined by the amino acid sequence of the protein in the region adjacent to the zinc-binding residues. This modular nature allows for the evolution of a vast array of DNA-binding specificities.