C2H2 Zinc Finger

**Semantic type:** Amino Acid Sequence

**Definition:** One of three structural motifs observed in DNA binding domains of zinc proteins. Domains in DNA- and RNA-binding proteins that contain amino acids which are folded into a single structural unit around a zinc atom that links two cysteines and two histidines. Each finger is postulated to recognize a specific sequence of about five nucleotide pairs. Originally identified in the TFIIIA transcription factor, it is also known as the C2H2 zinc finger.