Physiological consequences of the over-production of E. coli truncated molecular chaperone DnaJ.
In Escherichia coli one of the main molecular chaperones is DnaJ (hsp40) which mediates in a variety of highly conserved cellular process including protein folding reactions and assembly/disassembly of protein complexes. In this study we have investigated the toxicity of the over-production of DnaJ and two truncated polypeptides by examining growth rates, cell morphology and cell viability. Full-length DnaJ (1-375 amino acids) and truncated polypeptides, corresponding to the last 176 (containing the substrate binding domain) and 266 (containing the zinc finger-like domain) amino acids of the C-terminus of DnaJ, DnaJ delta 1-199 and delta 1-108 respectively, were over-produced via IPTG induction. High levels of synthesis were determined by SDS-PAGE and Western blotting using anti-DnaJ antibodies. The over-production of full-length DnaJ resulted in a low degree of filamentation and a decrease in cell viability. However, over-production of DnaJ truncated polypeptides, especially DnaJ delta 1-108, was bactericidal and resulted in a loss of viability and defective septation.
al-Herran
S
S
Department of Biomedical Sciences, University of Bradford, UK.
Ashraf
W
W
D004926:Escherichia coli / Q000166:cytology / Q000254:growth & development* / Q000648:ultrastructure; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D018832:Molecular Chaperones / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins; D017384:Sequence Deletion
C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins