Related ArticlesOptimization of an Escherichia coli system for cell-free synthesis of selectively N-labelled proteins for rapid analysis by NMR spectroscopy.
Cell-free protein synthesis offers rapid access to proteins that are selectively labelled with [15N]amino acids and suitable for analysis by NMR spectroscopy without chromatographic purification. A system based on an Escherichia coli cell extract was optimized with regard to protein yield and minimal usage of 15N-labelled amino acid, and examined for the presence of metabolic by-products which could interfere with the NMR analysis. Yields of up to 1.8 mg of human cyclophilin A per mL of reaction medium were obtained by expression of a synthetic gene. Equivalent yields were obtained using transcription directed by either T7 or tandem phage lambdapR and pL promoters, when the reactions were supplemented with purified phage T7 or E. coli RNA polymerase. Nineteen samples, each selectively labelled with a different 15N-enriched amino acid, were produced and analysed directly by NMR spectroscopy after ultracentrifugation. Cross-peaks from metabolic by-products were evident in the 15N-HSQC spectra of 13 of the samples. All metabolites were found to be small molecules that could be separated readily from the labelled proteins by dialysis. No significant transamination activity was observed except for [15N]Asp, where an enzyme in the cell extract efficiently converted Asp-->Asn. This activity was suppressed by replacing the normally high levels of potassium glutamate in the reaction mixture with ammonium or potassium acetate. In addition, the activity of peptide deformylase appeared to be generally reduced in the cell-free expression system.
Protein Interactions in the Escherichia coli Cytosol: An Impediment to In-Cell NMR Spectroscopy.
Protein Interactions in the Escherichia coli Cytosol: An Impediment to In-Cell NMR Spectroscopy.
Protein Interactions in the Escherichia coli Cytosol: An Impediment to In-Cell NMR Spectroscopy.
Chembiochem. 2011 Mar 29;
Authors: Crowley PB, Chow E, Papkovskaia T
Protein science is shifting towards experiments performed under native or native-like conditions. In-cell NMR spectroscopy for instance has the potential to reveal protein structure and dynamics inside cells. However, not all proteins can be studied by this technique. (15) N-labelled...
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03-31-2011 06:24 PM
Suppression of isotope scrambling in cell-free protein synthesis by broadband inhibition of PLP enymes for selective 15N-labelling and production of perdeuterated proteins in H2O
Suppression of isotope scrambling in cell-free protein synthesis by broadband inhibition of PLP enymes for selective 15N-labelling and production of perdeuterated proteins in H2O
Abstract Selectively isotope labelled protein samples can be prepared in vivo or in vitro from selectively labelled amino acids but, in many cases, metabolic conversions between different amino acids result in isotope scrambling. The best results are obtained by cell-free protein synthesis, where metabolic enzymes are generally less active, but isotope scrambling can never be suppressed completely. We show that...
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02-16-2011 09:34 PM
[NMR paper] Cell-free synthesis of 15N-labeled proteins for NMR studies.
Cell-free synthesis of 15N-labeled proteins for NMR studies.
Related Articles Cell-free synthesis of 15N-labeled proteins for NMR studies.
IUBMB Life. 2005 Sep;57(9):615-22
Authors: Ozawa K, Dixon NE, Otting G
Modern cell-free in vitro protein synthesis systems present powerful tools for the synthesis of isotope-labeled proteins in high yields. The production of selectively 15 N-labeled proteins from 15 N-labeled amino acids is particularly economic and yields are often sufficient to analyze the proteins very quickly by two-dimensional NMR...
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12-01-2010 06:56 PM
[NMR paper] Cell-free protein synthesis in an autoinduction system for NMR studies of protein-protein interactions.
Cell-free protein synthesis in an autoinduction system for NMR studies of protein-protein interactions.
Related Articles Cell-free protein synthesis in an autoinduction system for NMR studies of protein-protein interactions.
J Biomol NMR. 2005 Jul;32(3):235-41
Authors: Ozawa K, Jergic S, Crowther JA, Thompson PR, Wijffels G, Otting G, Dixon NA
Cell-free protein synthesis systems provide facile access to proteins in a nascent state that enables formation of soluble, native protein-protein complexes even if one of the protein components is prone...
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[NMR paper] Quantitation of protein expression in a cell-free system: Efficient detection of yiel
Quantitation of protein expression in a cell-free system: Efficient detection of yields and 19F NMR to identify folded protein.
Related Articles Quantitation of protein expression in a cell-free system: Efficient detection of yields and 19F NMR to identify folded protein.
J Biomol NMR. 2005 Jan;31(1):11-9
Authors: Neerathilingam M, Greene LH, Colebrooke SA, Campbell ID, Staunton D
We have developed an efficient and novel filter assay method, involving radioactive labelling and imaging, to quantify the expression of soluble proteins from a...
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[NMR paper] Reversible induction of ATP synthesis by DNA damage and repair in Escherichia coli. I
Reversible induction of ATP synthesis by DNA damage and repair in Escherichia coli. In vivo NMR studies.
Related Articles Reversible induction of ATP synthesis by DNA damage and repair in Escherichia coli. In vivo NMR studies.
J Biol Chem. 1998 Nov 13;273(46):30232-8
Authors: Dahan-Grobgeld E, Livneh Z, Maretzek AF, Polak-Charcon S, Eichenbaum Z, Degani H
Early metabolic events in Escherichia coli exposed to nalidixic acid, a topoisomerase II inhibitor and an inducer of the SOS system, were investigated by in vivo NMR spectroscopy, a technique...
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[NMR paper] Cell-free synthesis and amino acid-selective stable isotope labeling of proteins for
Cell-free synthesis and amino acid-selective stable isotope labeling of proteins for NMR analysis.
Related Articles Cell-free synthesis and amino acid-selective stable isotope labeling of proteins for NMR analysis.
J Biomol NMR. 1995 Sep;6(2):129-34
Authors: Kigawa T, Muto Y, Yokoyama S
For the application of multidimensional NMR spectroscopy to larger proteins, it would be useful to perform selective labeling of one of the 20 amino acids. For some amino acids, however, amino acid metabolism drastically reduces the efficiency and selectivity...
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Cell-free protein synthesis of perdeuterated proteins for NMR studies
Cell-free protein synthesis of perdeuterated proteins for NMR studies
Touraj Etezady-Esfarjani, Sebastian Hiller, Cristina Villalba and Kurt Wüthrich
Journal of Biomolecular NMR; 2007; 39(3); pp 229-238
Abstract:
Cell-free protein synthesis protocols for uniformly deuterated proteins typically yield low, non-uniform deuteration levels. This paper introduces an E. coli cell-extract, D-S30, which enables efficient production of proteins with high deuteration levels for all non-labile hydrogen atom positions. Potential applications of the new protocol may include production of proteins...
Optimization of an Escherichia coli system for cell-free synthesis of selectively N-l
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