scholarly journals The Effect of tRNA Derivatives Bound with Natural or Synthetic mRNA on the Interaction of Escherichia coli Ribosomes with Colicin E3

1975 ◽  
Vol 53 (2) ◽  
pp. 599-603 ◽  
Author(s):  
Yael KAUFMANN ◽  
Ada ZAMIR
Keyword(s):  
Escherichia Coli ◽  
Colicin E3 ◽  
Synthetic Mrna ◽  
Trna Derivatives

scholarly journals Transcriptional Profiling of Colicin-Induced Cell Death of Escherichia coli MG1655 Identifies Potential Mechanisms by Which Bacteriocins Promote Bacterial Diversity

2004 ◽  
Vol 186 (3) ◽  
pp. 866-869 ◽  
Author(s):  
Daniel Walker ◽  
Matthew Rolfe ◽  
Arthur Thompson ◽  
Geoffrey R. Moore ◽  
Richard James ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Transcriptional Profiling ◽  
Transcriptional Response ◽  
Chromosomal Dna ◽  
Transcriptional Responses ◽  
General Role ◽  
Bacterial Physiology ◽  
Translational Arrest ◽  
Colicin E3 ◽  
Colicin E9

ABSTRACT We report the transcriptional response of Escherichia coli MG1655 to damage induced by colicins E3 and E9, bacteriocins that kill cells through inactivation of the ribosome and degradation of chromosomal DNA, respectively. Colicin E9 strongly induced the LexA-regulated SOS response, while colicin E3 elicited a broad response that included the induction of cold shock genes, symptomatic of translational arrest. Colicin E3 also increased the transcription of cryptic prophage genes and other laterally acquired mobile elements. The transcriptional responses to both these toxins suggest mechanisms that may promote genetic diversity in E. coli populations, pointing to a more general role for colicins in adaptive bacterial physiology than has hitherto been realized.

scholarly journals Optimizing Cell-Free Protein Synthesis for Increased Yield and Activity of Colicins

2019 ◽  
Vol 2 (2) ◽  
pp. 28 ◽  
Author(s):  
Xing Jin ◽  
Weston Kightlinger ◽  
Seok Hoon Hong
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Cell Killing ◽  
Great Promise ◽  
Immunity Protein ◽  
Free Protein ◽  
Killing Activity ◽  
Colicin E1 ◽  
Colicin E3 ◽  
Cell Free Protein Synthesis

Colicins are antimicrobial proteins produced by Escherichia coli that hold great promise as viable complements or alternatives to antibiotics. Cell-free protein synthesis (CFPS) is a useful production platform for toxic proteins because it eliminates the need to maintain cell viability, a common problem in cell-based production. Previously, we demonstrated that colicins produced by CFPS based on crude Escherichia coli lysates are effective in eradicating antibiotic-tolerant bacteria known as persisters. However, we also found that some colicins have poor solubility or low cell-killing activity. In this study, we improved the solubility of colicin M from 16% to nearly 100% by producing it in chaperone-enriched E. coli extracts, resulting in enhanced cell-killing activity. We also improved the cytotoxicity of colicin E3 by adding or co-expressing the E3 immunity protein during the CFPS reaction, suggesting that the E3 immunity protein enhances colicin E3 activity in addition to protecting the host strain. Finally, we confirmed our previous finding that active colicins can be rapidly synthesized by observing colicin E1 production over time in CFPS. Within three hours of CFPS incubation, colicin E1 reached its maximum production yield and maintained high cytotoxicity during longer incubations up to 20 h. Taken together, our findings indicate that colicin production can be easily optimized for improved solubility and activity using the CFPS platform.

Decreased activity of colicins K-K235, A-CA31, C-CA57, and E2-CA42 upon sensitive Escherichia coli strains in the presence of cyclic 3′,5′–adenosine monophosphate

1974 ◽  
Vol 20 (10) ◽  
pp. 1443-1447
Author(s):  
M. Lavoie ◽  
L. G. Mathieu
Keyword(s):  
Escherichia Coli ◽  
Protective Effect ◽  
Cell Viability ◽  
Cyclic Nucleotides ◽  
Adenosine Monophosphate ◽  
Final Concentration ◽  
Triphenyltetrazolium Chloride ◽  
E Coli ◽  
Colicin E3 ◽  
Related Mode

The addition of cyclic 3′,5′-adenosine monophosphate (c-AMP) at a final concentration of 3 mM to nutrient broth significantly decreased the lethal activity of crude preparations of colicins A-CA31, K-K235, E2-CA42, and C-CA57 upon three different sensitive Escherichia coli strains. A protective effect of c-AMP on cell viability could also be shown in mixed cultures of the colicinogenic and the sensitive strains. Furthermore, the addition of c-AMP significantly reversed, in the sensitive E. coli ROW strain, the inhibition of triphenyltetrazolium chloride (TTC) reduction caused by the bacteriocins. However, the activities of colicin E3-CA38 on cell viability and reduction of TTC were not overcome markedly by exogenously added c-AMP. None of seven other cyclic nucleotides tested appeared to duplicate the protective effect of c-AMP against colicin A-CA31. The results indicate that for colicins K-K235, A-CA31, C-CA57, and E2-CA42 but not for colicin E3-CA38, there may be similar steps in the translocation of effects to sensitive targets and (or) a closely related mode of action reversible by c-AMP.

scholarly journals Bypass of receptor-mediated resistance to colicin E3 in Escherichia coli K-12.

1978 ◽  
Vol 136 (3) ◽  
pp. 1189-1191 ◽  
Author(s):  
M Tilby ◽  
I Hindennach ◽  
U Henning
Keyword(s):  
Escherichia Coli ◽  
K 12 ◽  
Colicin E3

scholarly journals Multiple Extracellular Loops Contribute to Substrate Binding and Transport by the Escherichia coli Cobalamin Transporter BtuB

2005 ◽  
Vol 187 (5) ◽  
pp. 1732-1739 ◽  
Author(s):  
Cynthia A. Fuller-Schaefer ◽  
Robert J. Kadner
Keyword(s):  
Escherichia Coli ◽  
Substrate Binding ◽  
High Specificity ◽  
Globular Domain ◽  
Colicin E1 ◽  
Extracellular Loops ◽  
Crystallographic Structures ◽  
Functional Relevance ◽  
Almost All ◽  
Colicin E3

ABSTRACT The Escherichia coli outer membrane TonB-dependent transporters for iron complexes and cobalamins recognize their multiple and diverse substrates with high specificity and affinity. The X-ray crystallographic structures of several transporters show that the substrate-binding surfaces are comprised of residues from the internal globular domain and multiple extracellular loops. The extracellular loops on the N-terminal half of the transmembrane beta-barrel of the cobalamin transporter BtuB participate in binding of the cofactor calcium atoms and undergo substantial conformation changes upon substrate binding. The functional relevance of the five C-terminal loops was examined by examining the effects of short in-frame deletions. Each loop contributed in different ways to the binding of BtuB substrates. Deletions in loops 7, 8, 9, and 11 strongly decreased cobalamin binding and transport, whereas deletions in loops 8, 9, and 10 affected binding and entry of phage BF23. None of the loops were essential for the action of colicin E1 or E3, which is consistent with the crystallographic observation that the colicin E3 receptor-binding domain can contact almost all of the loops. A deletion in loop 9 or 11 eliminated the ability of cobalamin to inhibit the action of colicin E1. These phenotypes show that there are multiple independent binding elements and point out similarities and differences in binding properties among the TonB-dependent transporters.

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