The fMet‐tRNA binding domain of translational initiation factor IF2: role and environment of its two Cys residues

FEBS Letters

Krafft, Christoph²  Welfle, Karin²  Gualerzi, Claudio O¹  Misselwitz, Rolf²  Welfle, Heinz²  Brandi, Letizia¹  Caserta, Enrico¹ 

[1] Laboratory of Genetics, Department of Biology, University of Camerino, 62032 Camerino (MC), Italy;Max-Delbrück-Centre for Molecular Medicine, D-13092 Berlin, Germany

关键词: Protein synthesis;    fMet-tRNA binding;    Protein domain;    Site-directed mutagenesis;    Protein unfolding;    Raman spectroscopy;    CD;    circular dichroism;    [Θ]220;    molar mean residue ellipticity at 220 nm;    ΔGNI and ΔGIU;    free energy of unfolding of native (N→I) and intermediate (I→U) states;    respectively;   

DOI  :  10.1016/S0014-5793(99)01280-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Mutations of the cysteines (positions 668 and 714) were generated in the IF2 C domain of Bacillus stearothermophilus translation initiation factor IF2. The corresponding proteins were characterized functionally and structurally. Most (yet not all) amino acid replacements at both positions resulted in severe reduction of the fMet-tRNA binding activity of IF2 C without grossly altering its structure. Our work demonstrates that: (a) both Cys residues are buried within an hydrophobic core and not accessible to protonation or chemical substitution, (b) neither Cys is functionally essential and (c) both Cys residues are located near the active site, probably without participating directly in fMet-tRNA binding.

【 授权许可】

Unknown