Zinc Finger Proteins in Gene Expression

The Xenopus 5S RNA gene-specific transcription factor IIIA (TFIIIA) was the first zinc finger protein characterized one decade ago (Klug and Rhodes 1987 Berg 1990 Rhodes and Klug 1993). This protein specifically binds to 

Evidence supporting the presence of several zinc-stabilized polypeptide loops in TFIIIA came from the results of limited proteolytic digestion (Miller et al. 1985). This was corroborated by EXAFS (extended X-ray absorption fine structure) measurements on 7S RNP particles (Diakun et al. 

The metal-coordinating properties of the Cys2His2 zinc fingers thus far studied reveal closely comparable affinities for the metal. Thus, recent measurements of the binding constants of zinc for CP-1, a synthetic single finger model peptide (Krizek et al. 1991), and for Moloney murine leukemia virus nucleocapside protein NCplO (Mely et al. 1991), as well as from Xenopus oocyte TFIIIA (Bienz 1992), are all close to 5 x when 

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