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Characterization of the domains of E. coli initiation factor IF2 responsible for recognition of the ribosome
Author(s) -
Moreno Juan Manuel Palacios,
Dyrskjøtersen Lars,
Kristensen Janni Egebjerg,
Mortensen Kim Kusk,
Sperling-Petersen Hans Uffe
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00858-3
Subject(s) - ribosome , initiation factor , 50s , eukaryotic ribosome , 30s , ribosomal rna , eukaryotic translation , eukaryotic large ribosomal subunit , ribosomal protein , eukaryotic small ribosomal subunit , biology , eukaryotic initiation factor , mutant , binding domain , microbiology and biotechnology , biochemistry , translation (biology) , chemistry , binding site , gene , rna , messenger rna
We have studied the interactions between the ribosome and the domains of Escherichia coli translation initiation factor 2, using an in vitro ribosomal binding assay with wild‐type forms, N‐ and C‐terminal truncated forms of IF2 as well as isolated structural domains. A deletion mutant of the factor consisting of the two N‐terminal domains of IF2, binds to both 30S and 50S ribosomal subunits as well as to 70S ribosomes. Furthermore, a truncated form of IF2, lacking the two N‐terminal domains, binds to 30S ribosomal subunits in the presence of IF1. In addition, this N‐terminal deletion mutant IF2 possess a low but significant affinity for the 70S ribosome which is increased by addition of IF1. The isolated C‐terminal domain of IF2 has no intrinsic affinity for the ribosome nor does the deletion of this domain from IF2 affect the ribosomal binding capability of IF2. We conclude that the N‐terminus of IF2 is required for optimal interaction of the factor with both 30S and 50S ribosomal subunits. A structural model for the interaction of IF2 with the ribosome is presented.