Lab Update // Brief Explanation of X-ray Crystallography

Lab Update: Currently we are still trying to crystallize our enzyme. We have tried 4 trays of different conditions, we found that some of the wells have formed crystals but not the type of crystal we need in order for x-ray diffraction to work properly. Although we have seen that in a few of the wells they formed the type of crystal we need  they are micro-crystals so we are unable to use them because they're too small. We have noticed that Polyethylene glycol (PEG) causes crystals to form for our protein and Lithium sulfate determines the size of the crystal. So we used this information to create a new set of potential wells for crystallization. We came up with: 0.2M Mg Acetate, TRIS Buffer, PEG 8000, pH 8.5 with this we create slight variations like changing the concentration or the pH.

X-ray Crystallography: After we get the ideal crystal form, we'll send it off to another lab that specializes in crystallography and there they'll perform x-ray diffraction. The whole purpose to crystallography is to give us a visual of the structure of the protein to better understand its function and x-ray diffraction is what let's us obtain this information.  First they start off with a three dimensional crystal and shoot x-rays through the crystal the x-rays are then diffracted in all directions, the diffracted beams are collected to create a picture of the enzyme.

X-rays Diffraction Pattern

This is a 3D-Structure of an enzyme.

Also here's a website if you want to read more about Protein Crystallography: http://www.jic.ac.uk/staff/david-lawson/xtallog/summary.htm#xrdc