Tandem translation of Bacillus subtilis initiation factor IF2 in E. coli Over‐expression of infB B.su in E. coli and purification of α‐ and β‐forms of IF2B.su

FEBS Letters

Sperling-Petersen, Hans Uffe²  Grunberg-Manago, Marianne¹  Hubert, Michel²  Shazand, Kamaran¹  Nyengaard, Niels Randel²  Mortensen, Kim Kusk²  Lassen, Søren Flensted² 

[1] Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005 Paris, France;Laboratory of Biodesign, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark

关键词: Bacillus subtilis;    Translation initiation factor IF2;    Recombinant protein expression;    Protein purification;   

DOI  :  10.1016/0014-5793(92)80920-C

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The protein synthesis initiation factor, IF2, in Bacillus subtilis has previously been characterized as being present in two forms, α and β, of molecular mass 79 and 68 kDa, respectively, on the basis of their cross-reaction with anti-E. coli IF2 antibodies and by the DNA sequence of the gene for IF2, infB _B.su. In this work we have cloned infB _B.su in E. coli cells. Two proteins of molecular mass identical to the B. subtilis IF2α and -β were over-expressed and purified using a new three-step ion-exchange chromatography procedure. The N-terminal amino acid sequence of the two proteins was determined and the results confirmed that the two forms were IF2α and -β, both encoded by the infB gene. The N-terminal amino acid sequence determined for IF2β is Met⁹⁴-Gln-Asn-Asn-Gln-Phe. The presence of methionine at position 94 shows that this form is, in fact, the result of a second translational initiation in infB _B.su mRNA, since the codon at amino acid position 94 is GUG, which is the normal codon for valine, but also known to be an initiator codon. This is a new example of the unusual tandem translation in E. coli of an open mRNA reading frame.

【 授权许可】

Unknown