Finger proteins and DNA‐specific recognition: Distinct patterns of conserved amino acids suggest different evolutionary modes

Abstract

Finger proteins, the first example of which was Xenopus TFIIIA, share Zn²⁺ finger-like folded domains capable of binding to nucleic acids. A large number of this type of protein have been characterised from diverse organisms, indicating a wide evolutionary spread of the DNA-binding fingers. At least two classes of finger proteins may be distinguished. Class I proteins contain variable numbers of the tandemly repeating TFIIIA-like finger motif, (Y/F-X-C-X_2–4-C-X₃-F-X₅-L-X₂-H-X₃-H). Class II finger proteins display a single (C-X₂-C-X₁₃-C-X₂-C) motif and a facultative second putative finger. The relation between the structure of finger proteins and their recognised DNA sequences is discussed.