Prof. Richard Ernst
Laboratorium fuer Physikalische Chemie
ETH-Zentrum. 8092 Zuerich, Switzerland

"Today, NMR of biomolecules vitally depends on the availability of isotopically labeled molecules. Many research groups are however unable to prepare the required sample because of their lack of experience in cloning and in the handling of expression systems. This applies in particular to my research group which consists of physical chemists interested in the dynamics of proteins.

We are extremely glad that there is a company, such as VLI Research Inc., which fills this gap and is willing to supply, under reasonable terms, isotopically labeled proteins of high purity. Without such a supplier, our research would be impossible."

Dr. Vladislav Orekhov
Swedish NMR Centre
Göteborg University
P.O. Box 465
SE 405 30 Göteborg

"We are glad to express our best attitude towards the isotope labelled products from VLI Research. High quality and long term stability of ubiquitin NMR samples purchased from VLI, are prerequisites for new methodology development and for setting up student laboratory exercises at the Swedish NMR Centre (www.nmr.se)."

Prof. Henriette Molinari
Lab. Risonanza Magnetica Nucleare
Consiglio Nazionale delle Ricerche

Professor Molinari leads a laboratory including a 500Mhz spectrometer at the University of Verona. The main emphasis of research deals with proteins from the lipocalin family plus those derived from VISCUM ALBUM and proteins binding both RNA and hydrophobic ligands. This research centers on the expression, structure and folding studies plus the electrostatic properties of the proteins.

"I can say that I have received very quickly the enriched sample of ubiquitin, exactly as we asked, in a sealed tube, and when we ran the spectra, the sample was perfectly okay. I also got from your office a very interesting offer on the expression and preparation of enriched proteins of our interest."

Dr. Eva Meirovitch
Department of Life Sciences
Bar-Ilan University
Ramat-Gan 52900, Israel

"I am writing to highlight the key role played by the isotope-labeled Ubiquitin samples acquired from VLI in the establishment of a new biostructural NMR program at BIU. Setting up the infrastructure for protein structure and dynamics research effectively, teaching this new discipline, and concomitantly pursuing work on a 24 kD protein, would have been impossible without using the VLI products as test samples and didactic material. I would like to express my appreciation to the VLI scientists and staff for an excellent job."

Dr. Mei Hong
Research Assistant Professor
Departments of Chemistry, Polymer Science & Engineering
University of Massachusetts
Amherst, MA 01003 USA

"We are very satisfied with the purity and stability of the ubiquitin that VLI expressed for us. We have recently started developing novel methods of protein isotopic labeling and required reliable and error-free expression of a model protein using such methods. VLI accomplished this custom synthesis competently, and within a reasonable time frame. The expertise of VLI and its high-quality service facilitated our research tremendously."

Dr. Norbert Zimmermann
BASF Aktiengesellschaft,
ZHV - B9, 67056 Ludwigshafen, Germany

"We at BASF have been totally satisfied about the quality of the ubiquitin protein. We have been able to test and implement new protein NMR methods much more quicker, as it would have been using a current protein sample out of our project pipeline, with the obvious shortcuts in stability and amount of material of "real life" protein samples. Improvable at VLI could be the time from ordering until delivery of the sample. Our order of predeuterated ubiquitin was fulfilled at a later date due to custom synthesis at VLI Research. The delivery of protein on stock at VLI was in contrast pretty fast and completely satisfactory."

Dr. John Cavanagh
Director
NMR Structural Biology
Wadsworth Center
New York State Department of Health
Albany, NY 12201 USA

"I have been very pleased with our choice to use ubiquitin (both ¹⁵N and ¹⁵N/¹³C labeled) as the model protein in my lab. Not only was the protein used throughout our textbook, giving the text great uniformity, but we use the doubly labeled sample in the design of new and improved NMR methodologies. Having the assignments for all nuclei in the protein makes it absolutely ideal for NMR methods development work."

Dr. Marc Baldus
Solid-state NMR Group
MPI for Biophysical Chemistry
Göttingen, Germany

As a research group interested in the development of solid-state NMR for biophysical applications, we have been successfully working with U-[¹³C,¹⁵N] labeled Ubiquitin for several years (see references below). Samples obtained from VLI research could be readily used for our investigations and were stable over extended time periods. As visible from a ¹³CP MAS spectrum of a hydrated U-[¹³C,¹⁵N] labeled sample (recorded on a 600 MHz WB NMR spectrometer using TPPM2 proton decoupling), high-resolution ¹³C spectra are readily obtained and confirm the high quality of the VLI ubiquitin products.

References

1. Luca, S.; Baldus, M. J. Magn. Reson. 2002, 159, 243-249; Lange, A.; Luca, S.; Baldus, M. J. Am. Chem. Soc. 2002, 124, 9704-9705; Sonnenberg, L.; Luca, S.; Baldus, M. J. Magn. Reson. 2003, in press.
2. Bennett, A. E.; Rienstra, C. M.; Auger, M.; Lakshmi, K. V.; Griffin, R. G. J. Chem. Phys. 1995, 103, 6951-6958.