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X-ray Crystallography

Product Introduction


X-ray crystallography is a discipline to study the arrangement of atoms in crystals by using X-ray technique. Crystal structure can provide visualized answers for the following scientific issues: protein folding mechanism, the binding of substrate and ligand, functional atoms or residues. X-ray crystallography is applied to determine the structure and study the function of biomacro-molecules, such as protein and DNA. Nowadays, X-ray crystallography is widely used in molecular biology and drug development.

Advantages

  • Project evaluation for free.
  • High throughput automated crystallization screening.
  • Relying on Shanghai synchrotron radiation source.
  • The deliverable data conforms to the PDB data submission standard.

Project Workflow

Turnaround Time

Within 3~6 months from crystallization to data analysis.

Sample Requirement

The protein sequence can be directly provided, or the recombinant vector.

Frequently Asked Questions

 

What materials should be provided for project evaluation?

Because the physical and chemical properties of proteins and biochemical properties are very different, please offer the name, molecular weight, source species and amino acid sequence of your intention protein. If you pay attention to the structure of protein complex, please provide the affinity data to us.

What the effect does the homologous structure on the structure analysis have?

With homologous structure (homology >30%), the phase problem can be solved by molecular replacement method and the pro- tein structure is resolved consequently. Only a set of diffraction data needs to be collected, and the calculation method is simple. Without homologous structure, the phase problem needs to be solved by multi-wavelength anomalous scattering and then deter- mined the protein structure. Two sets of diffraction data need to be collected, and the calculation method is much complicated. The diffraction data of SeMet-labeled protein and native protein should be collected respectively. Generally speaking, structure analysis is relatively difficult without homologous structure

How do I send the protein solution?

First of all, ensure that protein was not treated by freeze-thaw cycle, because freeze-thaw cycle will cause protein denaturation. 4℃ ice pack or -80℃ dry ice pack is recommended.

What is the protein concentration during transport?

The protein can be delivered in any concentration, just adding a tube of protein buffer.


Protein crystallization and optimization.

Through the high-throughput automated screening method, more than 1,000 buffer conditions were screened. After the crystal growth was observed, the crystallization conditions of the protein were optimized to obtain high quality single crystal finally.


Protein diffraction data collection and refinement statistics.

HKL 3000 was used to process the diffraction data, thus a series of parametric data such as crystal cell parameters, angle units, integri- ty, effective signal strength and signal-to-noise ratio were obtained.

XXX
Wavelength 0.979
Space group C121
a,b,c (Å) 105.361 109.653 134.130
α,β,γ (°) 90.00 99.41 90.00
Resolution (Å) 50.00-2.50 (2.54-2.50)
No. of observations 355895
No. of unique reflections 51857
Completeness (%) 99.9(100.0)
<I>/δ(I) 13.6 (2.3)
Redundancy 6.9 (6.7)
Rmerge 0.138 (0.529)
Rp.i.m 0.063 (0.245)
Rwork /Rfree 0.17/0.21

Protein 3D structure

The protein 3D structure data conforms to the Protein Date Bank (PDB) data submission standard, and meets the article publication standard: R free is lower than 0.3, R work is lower than 0.25.