What are the main difficulties of x-ray crystallography?

The main difficulties of X-ray crystallography include:

1. It is very difficult to obtain crystals with high diffraction quality and proper size.

2. Phase analysis. In theory, X-ray crystallography technology has no requirement for the molecular weight of protein, and can obtain any high-resolution structure at the atomic level of protein. Because some proteins are very difficult to crystallize, or the quality of crystallization is very poor, there is no diffraction or only very low resolution diffraction data, which limits the X-ray crystallography analysis of protein structure.

Explanation:

http://www.creative-biostructure.com/protein-crystallization_26.htm

regents of the university of california v. bakke, 438 u.s. 265 (1978), was a landmark decision by the supreme court of the united states. it upheld affirmative action, allowing race to be one of several factors in college admission policy.