What Is a Zinc Finger?
A zinc finger is a finger-shaped protein fold that is formed by specific amino acids in the protein binding to a zinc ion. Zinc finger proteins often bind to DNA and RNA because their shape allows close interaction of the domain with the nucleotides of DNA and RNA. Their nucleotide binding properties allow them to function in regulating gene expression and in virus assembly. There are several types of zinc finger structures, but the most common version consists of an alpha helix and a beta sheet, the two most common secondary structures in proteins, on either side of at least one zinc ion. The alpha helix and beta sheet are held in position by cystine and histidine residues, coordinating the zinc ion via their nitrogen and sulfur atoms. The zinc finger binds to DNA, and through the interaction of amino acids at the periphery of the zinc finger with base pairs at the center of the DNA double helix. It is a compact protein domain, and its small size allows it to have close proximity with
