X-Ray Crystallography: Limitations and Drawbacks for Technical Audiences
X-ray crystallography is a technique used to determine substances’ atomic and molecular structure by analyzing the diffraction patterns produced by X-rays that pass through a crystalline sample. While this technique has revolutionized the field of structural biology and enabled scientists to understand the properties and behavior of proteins better, drug developers need to consider several limitations and drawbacks.
- Crystalline samples
The requirement for a crystalline sample is one of the most significant restrictions of x-ray crystallography. Especially with biomolecules, crystallizing proteins in the lab can be time-consuming and challenging because most proteins are not naturally crystalline. Complex, big, or membrane-embedded proteins frequently cause them to fail. Even if crystals are obtained, their quality might not be high enough to generate a structure with high resolution.
However, companies such as Immuto have developed platforms that use proprietary protein engineering approaches to generate highly stable proteins, which can be more easily crystallized and yield better quality structures than traditional methods.
- Model building
Model construction is another x-ray crystallography limitation. There are ambiguities in the model since it is frequently challenging to visualize the whole molecule inside the crystal due to the nature of crystal packing. Also, due to the diffraction data’s limited resolution, there can be unresolved areas or artefacts in the structure. One solution to these limitations is to combine X-ray crystallography with other techniques, such as electron microscopy or nuclear magnetic resonance spectroscopy, to obtain a complete picture of the molecule.
- Background noise
Background noise is another drawback of x-ray crystallography. The diffraction patterns produced by X-rays passing through a crystal contain signal and noise, and separating the two can be challenging. This noise can lead to inaccuracies in determining the structure and make data analysis more complex. However, new software and algorithms are continually being developed to improve the structure determination’s accuracy and make data analysis more efficient.
- Cost and accessibility
Finally, the cost and accessibility of x-ray crystallography can be a limiting factor for many research groups. Synchrotron sources, which generate high-intensity X-rays for crystallography, are limited and expensive. Also, it can take several attempts to crystallize your protein and obtain helpful information from the scattering trials, increasing the expense associated with your program. The x-ray crystallography equipment and software can also be costly. However, some companies, such as Immuto, have developed cost-effective approaches to protein expression and crystallization, making the technique more accessible to researchers.
Despite its drawbacks and weaknesses, X-ray crystallography is an effective method for figuring out the structures of proteins and other biological molecules. The precision and effectiveness of the technique are continually being enhanced by developments in protein engineering, software, and data analysis, making it an essential tool for drug discovery and structural biology.
Immuto’s platform is built to overcome the challenges around needing a crystalline sample, model-building artefacts and limitations, background noise and data analysis, and cost and accessibility.
In conclusion, x-ray crystallography has its limitations and disadvantages. Still, drug developers should also be aware of its promise and the ongoing developments in the area that resolve these issues and not slow their progress.