<molecular biology> A specialised protein group that is characterised by a single zinc atom associated with DNA binding proteins. A loop of 12 amino acids contains either 2 cysteine and 2 histidine groups (a cysteine histidine zinc finger) or 4 cysteines (a cysteine cysteine zinc finger), that directly co ordinate a zinc atom. The loops (usually present in multiples) intercalate directly into the DNA helix. Originally identified in the RNA polymerase III transcription factor TFIIIA.

(11 Mar 2008)