TFIIIA:Type 1 Promoter complex DNA with RNA Polymerase III Type 1 Closed Promoter Binding of TFIIIA To type 1 Promoter Authored: Hernandez, N, 2003-09-11 07:42:29 Edited: Gillespie, ME, 0000-00-00 00:00:00 Pubmed1438283 Pubmed7001457 Pubmed7789179 Pubmed9242690 Reactome Database ID Release 4376052 Reactome, http://www.reactome.org ReactomeREACT_1545 TFIIIA contains nine C2H2 zinc fingers (Arakawa et al., 1995). It binds to both the ICR region of the 5S RNA genes and to 5S RNA to form the 7S storage ribonucleoprotein particle (Pelham and Brown, 1980). Upon TFIIIA binding to the 5S gene, the TFIIIA zinc fingers are aligned over the length of the ICR with the C-terminal zinc fingers in proximity to the 5 end, and the N-terminal zinc fingers in proximity to the 3 end, of the ICR. Zinc fingers 1-3 contact the C block within the ICR and have been reported to contribute most of the binding energy of the full-length protein (Clemens et al., 1992). However, TFIIIA fragments containing zinc fingers 4-9 bind to the A block and intermediate element within the ICR with affinities close to those of the full-length protein. This and other observations suggest that simultaneous binding by all nine TFIIIA zinc fingers requires energetically unfavorable distortions within the DNA, the protein, or both (Kehres et al., 1997).