Domain of E. coli translational initiation factor IF2 homologous to lambda cI repressor and displaying DNA binding activity.
The carboxy-terminal region of translational initiation factor IF2 is a common region to the three active forms of the factor (alpha, beta and gamma) but its function is still unknown. We report here that this region of IF2 carries at least one domain which is homologous to the N-terminal and middle part of the cI repressor of lambda phage. The IF2 homologous domain harbors functionally important features of the lambda repressor, e.g. the helix-turn-helix motif and some of the residues essential for the structure of the hydrophobic core of the repressor. This homologous domain of IF2 was fused to the beta-galactosidase protein. The hybrid protein, as well as IF2 itself, shows a consistent DNA binding activity in nitrocellulose filtration assays but does not display the specificity of the cI repressor for the PR operator. The implication of this domain in the transcriptional activity of IF2, reported by others, is discussed.
Vachon
G
G
Institut de Biologie Moléculaire et d'Ingénierie Génétique, URA CNRS 1172, Université de Poitiers, France.
Raingeaud
J
J
Dérijard
B
B
Julien
R
R
Cenatiempo
Y
Y
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D010448:Peptide Initiation Factors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D010957:Plasmids; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; D001616:beta-Galactosidase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D010448:Peptide Initiation Factors; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D001616:beta-Galactosidase