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Biophysical Characterization of Effect of Zinc on Eukaryotic Translation Initiation Factor 4B
Author(s) -
Sultana Shemaila,
Gallie Daniel R,
Goss Dixie J
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.499.10
Subject(s) - eif4a , chemistry , rna , eukaryotic initiation factor , eukaryotic translation , initiation factor , zinc , biochemistry , messenger rna , translation (biology) , biophysics , microbiology and biotechnology , stereochemistry , ribosome , biology , gene , organic chemistry
Eukaryotic translation initiation factor 4B promotes RNA dependent ATP hydrolysis and ATP dependent RNA helicase activity of eIF4A and eIF4F. It has recently been reported that eIF4B also organizes assembly of the RNA, eIFiso4G, eIF4A, and poly‐(A) binding protein and zinc enhances the RNA binding and interaction with PABP. By the use of fluorescence spectroscopy, native protein tryptophan fluorescence, and fluorescence labeled RNA as internal molecular probes we are characterizing these interactions. We previously reported that zinc binds tightly with eIF4B, K d of 19.7 nM (J Biol Chem. 2008 Dec 26; 283(52):36140–53). The Kd of binding of eIF4B with 20mer poly (A) RNA is 77 ± 7 nM and in presence of zinc it lowers down to 45 ± 3 nM. There was no significant difference between the binding of eIF4B full length and eIF4B (320–527) deletion mutant with 20mer poly(A) RNA. Circular dichroism showed that addition of zinc resulted in a more than 50% decrease in alpha content of the eIF4B protein. Biophysical characterization of the effect of eIF4B versus eIF4B‐Zn and its interactions with other (eIF) factors is also carried out. Supported by National Science Foundation grant MCB 0814051