|MoBio||Zinc Finger||Chapter 4|
The zinc finger motif contains one or more zinc ions which are crucial for the structural stability. It can be divided into three types: C2H2, C4, and C6.
C2H2 zinc finger:
It is characterized by the sequence CX2-4C....HX2-4H, where C = cysteine, H = histidine, X = any amino acid. In the 3D structure, two cysteine residues and two histidine residues interact with a zinc ion.
C4 zinc finger:
Its consensus sequence is CX2CX13CX2CX14-15CX5CX9CX2C. The first four cysteine residues bind to a zinc ion and the last four cysteine residues bind to another zinc ion.
C6 zinc finger.
It has the consensus sequence CX2CX6CX5-6CX2CX6C. The yeast's Gal4 contains such a motif where six cysteine residues interact with two zinc ions.