Biomolecular NMR

Intact Proteins and Protein Standards

Nexomics® Protein Standards

Stable Isotope-Labeled Standards and XF-1 Protein Pairs for X-Filtered NOESY – new and exciting isotope-enriched proteins for use as standards in NMR spectroscopy. 

• Aiding in the development of new pulse sequences
• Optimizing parameters for a given pulse sequence
 

 


  • Nexomics® Protein Standards

Cambridge Isotope Laboratories, Inc. (CIL) is pleased to offer new and exciting isotope-enriched proteins for use as standards in NMR spectroscopy. Isotope-enriched protein standards are ideal for:

• Aiding in thILV and ILVFY Protein Standardse development of new pulse sequences
• Optimizing parameters for a given pulse sequence
• Assessing spectrometer performance
• Training purposes 

High-quality, high-purity standards from Nexomics  are invaluable tools for bioNMR. Each product is accompanied by the following data:

• 1 H-15N HSQC (15N-labeled proteins)
• 1 H-13C HSQC (13C-labeled proteins)
• CO-NH projection of 3D HNCO ( 15N,13C-labeled proteins)
• SDS PAGE (for all labeled proteins)
• MALDI-TOF (for all labeled proteins)
• 15N-edited X-filtered 2D NOESY (NEX-XF1)

Maltose Binding Protein (NEX-MBP)
NEX-MBP is a 44.9 kDa monomeric protein for which multiple sets of resonance assignments (BMRB database) and 3D structures (PDB database) are publicly available. This product is uniformly 2H,15N,13C-enriched with selective incorporation of protons into methyl groups of Ile-δ1, Leu-δ and Val-γ side chains. As nonuniform sampling (NUS) and other NMR techniques emerge to push the size limitations of NMR to new boundaries, large protein standards, such as NEX-MBP, will be required to test data-collection and processing strategies.
 
Maltose Binding Protein Chart
 
 
NEX-MBP sample formulations:
NEX-MBP1: Apo Conformation 0.5 mM 2H,15N,13C and ILV methyl 1H,13C MBP in 10% D2O, 0.02% NaN3, 20 mM sodium phosphate @ pH 7.2
NEX-MBP2: Closed Conformation 0.5 mM 2H,15N,13C and ILV methyl 1H,13C MBP with 3 mM maltotriose, 10% D2O, 0.02% NaN3, 20 mM sodium phosphate @ pH 7.2
NEX-MBP3: Open Conformation 0.5 mM 2H,15N,13C and ILV methyl 1H,13C MBP with 2 mM β-cyclodextrin, 10% D2O, 0.02% NaN3, 20 mM sodium phosphate @ pH 7.2 
 
 
image: "Open" (blue) and "closed" (red) superposition
 
 
 

 
X-Filtered NOESY NMR Standard (NEX-XF1)
In an X-filtered experiment, only NOEs between 15N/13C-1H and 14N/12C-1H (e.g. interchain NOEs) protons are observed. NOEs between protons connected to 15N,13C are filtered (intrachain NOEs). When uniformly double-labeled protein sample is mixed with a naturalabundance protein sample, the interface will give rise to the only observable NOESY cross peaks. This powerful strategy enables the spectroscopist to discern
intra from inter NOESY cross peaks, thereby providing essential distance constraints for defining the dimer interface (Lee, et al., 1994, 350:87; Palmer, et al., 1991, 93:151; Schleucher, et al., 1994, 4:301).

NOESY NMR Standard Products

 
NEX-XF1 is a 16 kDa protein (A. fulgidus antitoxin vapB21 homodimer) for which a set of resonance assignments (bmr7362), 3D structure (2NWT) and other NMR data are available in the public domain. This is a mixture of unlabeledand uniformly 15N,13C-enriched protein (25% homodimer unlabeled; 50% heterodimer unlabeled/labeled; 25% homodimer labeled) and is perfect to set up X-filtered NOESY experiments.
 
NEX-XF1 homodimer sample formulation:
NEX-XF1: 13C,15N-labeled and unlabeled sample conditions1 mM protein, 20 mM NH4OAc pH 5.5, 100 mM NaCl, 5 mM CaCl2, 10% D2O, 0.02 % NaN3
 
 

Ubiquitin (NEX-UB1) 

NEX-UB1 is a small 8.8 kDa monomeric protein for which multiple sets of resonance assignments (BMRB database) and 3D structures (PDB database) are publicly available. This protein standard is uniformly 15N, 13C-enriched. Ubiquitin has been used as an industry-wide standard in the protein NMR field for many years. NEX-

UB1 sample formulation: 
NEX-UB1: Uniformly 15N, 13C-labeled ubiquitin in 90% H2 O; 10% D2 O 10 mM sodium phosphate buffer, pH 6.5

For a list of Ubiquitin (NEX-UB1) Products, Request a Quote or Order click here

 

 

Frequently Asked Questions 

 

 

Frequently Asked Questions 

Does Nexomics sell other proteins?

Yes. Please direct customers to contact Nexomics directly for inquiries regarding requests for other proteins. Please have the customer email Greg Kornhaber (gkornhaber@nexomics.com) with their request.

Can the customer obtain a solution with a different concentration than those that are listed?

Yes. We suggest concentrations of 0.25 mM, 0.5 mM and
1 mM.

How are these products priced?

The price is based on the number of milligrams the solution
contains.

Can these be used for non-NMR use?

Yes, although ubiquitin is expected to be the only protein that
would have a wider applicability beyond NMR use. For example,
ubiquitination (the process of adding a ubiquitin molecule to
a protein) is a common protein post-translational modification
and is of interest to cellular biologists and the pharmaceutical
industry.
 

What information does the customer need to specify to receive a quote?

The following information is required:
• The name of the protein
• The desired labeling, volume, and concentration
• If they want it packaged in an NMR tube or an ampoule.
 
If they want it in an NMR tube, they must specify the size
(e.g., 5 mm or 3 mm)
 

What is an X-filtered NOESY experiment?

It’s a type of NMR experiment that obtains signals resulting
from two molecules that bind to one another. The experiment
can distinguish which parts of the molecules that are involved
in binding. This type of information is

How are the protein standards packaged?

They come packaged in eppendorf tubes, however, upon request, they can come packaged in NMR tubes. Norell's Secure Series™ 3 mm (Norell Cat No. S33-0900-030-1780) and 5 mm (Norell Cat No. S33-0900-050-1780) tubes are used in this case.  Please visit http://www.nmrtubes.com/secure-series.php for more information regarding Norell's Secure Series™ NMR tubes.  Standard fill volumes for 5 mm tubes is 650uL and for 3 mm tubes is 250uL. Other volumes may be requested. 

Kevin Millis, PhD

Kevin Millis, PhD

Senior Scientist, Application Development Manager

Kevin Millis, PhD, is the Senior Scientist and Market Development Manager for all NMR and Mass Spectrometry product lines. Kevin is responsible for Technical Services both internally and externally for all CIL customers as well as being responsible for the application and market development for the CIL products.

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