The N-terminal half of initiation factor IF3 is folded as a stable independent domain.
Initiation factor IF3 plays an essential role in the initiation of protein translation by binding to the 30S ribosomal subunit and selecting a proper tRNA(fMet)/initiation codon complex. The domain structure of IF3 from Escherichia coli has been investigated by limited proteolysis followed by mass spectrometry and protein sequencing of the resulting peptides. This analysis revealed a highly segmented structure with two independent domains connected by a charged linker peptide, highly susceptible to proteolytic cleavage. The N-terminal domain is very stable and comparison of its 2-D NMR spectrum with that of intact IF3 revealed that it retains its three-dimensional fold.
Fortier
P L
PL
Laboratoire de Biochimie, URA 240 du CNRS, Ecole Polytechnique, Palaiseau, France.
Schmitter
J M
JM
Garcia
C
C
Dardel
F
F
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry; D039621:Eukaryotic Initiation Factor-3; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010448:Peptide Initiation Factors / Q000737:chemistry*; D017510:Protein Folding
D001426:Bacterial Proteins; D039621:Eukaryotic Initiation Factor-3; D010448:Peptide Initiation Factors