Zinc-coordinating DNA-binding domains C2H2 zinc finger factors CLASSLINK:http\://www.edgar-wingender.de/class 2.3.html Class TRANSFAC^® class description C0001: Zinc finger motif of TFIIIA/Krueppel type. Each finger comprises 2 cysteine and 2 histidine residues coordinating one zinc ion, in some cases one histidine is replaced by another cysteine. The zinc ion is essential for DNA-binding. The first half of the finger sequence is generally organized in two antiparallel beta-strands, the second half as an alpha-helix and partly as an 310-helix. Hydrophobic contacts between the beta-strands and the alpha-helix are formed by the conserved phenylalanine and leucine residues. The alpha-helix binds to DNA through the major groove. The finger link frequently is TGEKPY.