Structural studies on proteins by nuclear magnetic resonance (NMR) require labelling of these molecules with stable isotopes. Organisms such as bacteria and yeast are used to express these proteins. Silantes offers a wide range of stable isotope-labelled cell growth media to express stable isotope-labelled proteins.
Available in Multiple Variations, Tailored to Your Needs
Depending on your application and purpose, we designed different media variations for the expression of stable isotope-labelled proteins in E.coli and yeast. Yeast is used for the expression of eukaryotic proteins, since this host facilitates a high protein expression and many post-translational protein modifications which are characteristic for mammalian cells.
Silantes also offers stable isotope labelled reagents for M9 media such as 13C-glucose, D2O and 15NH4Cl.
High Standards in Quality Control
The Silantes media are tested for reproducible fermentation results. Moreover, each batch is adjusted to guarantee consistent cell densities. The media are available in all combinations of the isotopic labels 2H, 13C, 15N with an isotopic enrichment of > 98 %. This isotopic enrichment is tested by mass spectrometry. The biological competence is tested by growth tests. The quality control test results are sent to the customer with each shipment.
No Additional 13C-glucose Needed
All Silantes cell growth media are prepared from uniformly labelled bacterial cell hydrolysate of Ralstonia eutropha containing carbon as energy source. Therefore, there is no additional 13C-glucose necessary to express 13C-labelled proteins if the media are used as stand-alone media.
The Silantes OD2 Media Solution is the high-performance line amongst the range of Silantes stable isotope-labelled cell growth media for the expression of stable isotope-labelled proteins.
Ready-to-Use Rich Growth Medium
The Silantes OD2 media are rich growth media solutions. They are sterile and Ready-to-Use for fermentations. The media are made from isotopically labelled bacterial hydrolysate and contain primarily amino acids, some low molecular weight oligopeptides and almost no carbohydrates. The bacterial strain used is a chemolithoautotrophic organism which grows on inorganic substrates that are isotopically labelled.
Quote by Dr. Leonardo Gonnelli, CERM, Centro di Risonanze Magnetiche, Universita di Firenze, Italy:
"Protein expression can be easily optimized in Silantes medium and often the best conditions found in LB standard medium can be used. Silantes saves your time! Silantes media are an excellent opportunity to get labelled samples for MR studies, especially if you need a fast preparation for high-throughput targets. Today, most of the labelled samples of our lab are prepared using Silantes media."
Excellent Performance, Especially in D2O
The Silantes OD2 medium is developed for a high-performance expression of stable isotope labelled proteins. The media are adjusted in salt conditions formulated for a > OD600 2 cell density within 24 h. The growth performance and cell densities are comparable to 0,4 % glucose M9 medium.
Figure 1 shows the growth curve of E.coli in 2H-labelled Silantes OD2 Media Solution for E.coli and in 1 % unlabelled Silantes SILEX Powder Media for E.coli in D2O. The figure shows that both media have the same excellent performance and exceed OD 2.5 in less than 24 hours.
Figure 1: Growth of E.coli 2H-labelled Silantes media solution and in Silantes powder media in D2O
Quote by Prof. Dr. Harald Schwalbe, Johann Wolfgang-Goethe-Universität, Frankfurt, Germany:
"We have used Silantes expression media for protein expression. The yields were with the first trial superior to our results using minimal medium. I can strongly recommend using the products by Silantes."
Quote by Dr. Stefan Prytulla, M-Phasys, Tübingen, Germany:
"After purification, we obtained about 35 mg of pure protein with the D15N-labelled Silantes OD2 Media. This is even a few milligrams more than we usually get from LB cultures. "
Figure 2 and figure 3 show SDS-PAGEs as an example of protein expressions using M9 media and Silantes OD2 Media for ubiquitin and RNA polymerase α-subunit. The figures show that the yield is higher when Silantes OD2 Media are used. Generally, the heterologous protein expression performance using Silantes OD2 medium is similar as with LB medium.
Figure 2 and Figure 3: SDS-PAGE of Ubiquitin (left) and SDS-PAGE of RNA-Polymerase a-subunit
Quote by Dr. Klaus Fiebig, Frankfurt University, Frankfurt, Germany:
"We compared Silantes unlabelled media with Silantes 13C15N-labelled media and found no substantial differences in growth or expression rates. We have enclosed data of a typical growth curve and the resulting protein yield obtained in the same system, using 15N-labelled M9 medium. Silantes media give extraordinarily high results compared to common M9 media."
Quote by Prof. Sklenar, Masaryk University, 2001:
"The result (of the Silantes OD2 Media) was comparable to typical rich growth media, the yield (expression of MUP1) of the Silantes OD2 Media was two-times higher; the growth parameters were good. Silantes OD2 Media are very convenient to use."
Flexibility in Cell Growth
Silantes SILEX and ECO are two different powder media developed to give a high flexibility in cell growth experiments for the expression of stable isotope labelled proteins. Both media can be used as stand-alone media or as a supplement to M9 experiments.
Diagram 3 shows that using the powder media as a supplement to M9 increases the cell growth rates.
Figure 3: Growth of E.coli in different media
The graph shows the growth curves of E.coli in M9 medium, in M9 medium supplemented with 1g/L 15N-SILEX powder and in 15N-labelled stand-alone (10g/L) SILEX powder media.
SILEX Powder Media for High Performance
SILEX powder is a lyophilizate from the High Performance OD2 Rich Growth Media (see above) which are made from isotopically labelled bacterial hydrolysate containing primarily amino acids, somelow molecular weight oligopeptides and almost no carbohydrates.
Therefore, Silantes SILEX Powder Media are designed for high cell growth rates and high protein expression yields.
This excellent performance is also applicable to cell growths in deuterated environment: Figure one (see above) shows that stand-alone (10 g/L) SILEX Powder Media in D2O exceed OD 2.5 in less than 24 hours.
The ECOnomic Alternative
The Silantes ECO powder media are an economic alternative to SILEX media. They contain a defined amount of SILEX powder, labelled amino acids, low MW oligopeptides, carbohydrates, and salts.
The economic concept: 13C- or 13C15N-labelled ECO Media are offered below the costs of a respective M9 experiment (including 13C-glucose and/or 15N-ammonium). Yet, ECO media have a higher performance. In this way, the costs per OD are lower when using Silantes ECO media compared to M9 experiments.