Proteolysis of Bacillus stearothermophilus IF2 and specific protection by fMet-tRNA.
Translation initiation factor IF2 from Bacillus stearothermophilus (741 amino acids, Mr 82,043) was subjected to trypsinolysis alone or in the presence of fMet-tRNA. The initiator tRNA was found to protect very efficiently the Arg308-Ala309 bond within the GTP binding site of IF2 and, more weakly, three bonds (Lys146-Gln147, Lys154-Glu155 and Arg519-Ser520). The first two are located at the border between the non-conserved, dispensable (for translation) N-terminal portion and the conserved G-domain of the protein, the third is located at the border between the G- and C-domains. Since IF2 is known to interact with fMet-tRNA through its protease-resistant C- (carboxyl terminus) domain, the observed protection suggests that, upon binding of fMet-tRNA, long-distance tertiary interactions between the IF2 domains may take place.
Severini
M
M
Department of Biology, University of Camerino, Italy.
Choli
T
T
La Teana
A
A
Gualerzi
C O
CO
D000595:Amino Acid Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D015852:Eukaryotic Initiation Factor-2 / Q000737:chemistry / Q000378:metabolism*; D001411:Geobacillus stearothermophilus / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D012358:RNA, Transfer, Met / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism
D015852:Eukaryotic Initiation Factor-2; D012358:RNA, Transfer, Met; D006160:Guanosine Triphosphate; D014357:Trypsin