EXAFS study of the zinc-binding sites in the protein transcription factor IIIA

The protein transcription factor IIIA (TFIIIA) is involved in the synthesis of 5S RNA in vitro by RNA polymerase III. It can be isolated from Xenopus laevis oocytes as a 7S particle in which the protein is associated with 5S RNA. Recently it has been shown that the native particle contains 7-11 zinc...

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Bibliographic Details
Published inNature (London) Vol. 324; no. 6098; p. 698
Main Authors Diakun, G P, Fairall, L, Klug, A
Format Journal Article
LanguageEnglish
Published England 18.12.1986
Subjects
Animals
Binding Sites
Electron Probe Microanalysis - methods
Female
Fourier Analysis
Oocytes - metabolism
Protein Binding
Transcription Factor TFIIIA
Transcription Factors - metabolism
Xenopus
Zinc - metabolism
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Summary:The protein transcription factor IIIA (TFIIIA) is involved in the synthesis of 5S RNA in vitro by RNA polymerase III. It can be isolated from Xenopus laevis oocytes as a 7S particle in which the protein is associated with 5S RNA. Recently it has been shown that the native particle contains 7-11 zinc atoms. Analysis of the amino-acid sequence of TFIIIA revealed nine similar domains of approximately 30 amino acids, each containing two invariant pairs of histidines and cysteines, which have been implicated as possible binding sites for the zinc atoms. Other regulatory proteins with sequence homology to the zinc-binding domains of TFIIIA have now been reported. Here, we report the results of an EXAFS (extended X-ray absorption fine structure) study of TFIIIA which shows that the coordination sphere of the zinc sites consists of two cysteine and two histidine residues.
ISSN:0028-0836
DOI:10.1038/324698a0