Fan Lecture 1

Question 1

What is contained in a PDB file?

Answer 1

PDB = Protein Data Bank
- header: experimental conditions
- list of atoms and their coordinates

Question 2

Why is x-ray used?

Answer 2

as a ruler
- wavelength = distance between 2 peaks
- phase = distance relative to origin
- amplitude = x-axis to top of peak

Question 3

What is a crystal?

Answer 3

unit cell and its contents being repeated in a periodic manner along unit cell axes

Question 4

Why are crystals used?

Answer 4

highly ordered arrangement of atoms or molecules that allow scientists to determine the positions of atoms within the lattice
- when x-rays are directed at a crystal, the regular spacing of atoms within the lattice causes the incoming radiation to diffract in specific patterns

Question 5

How do you prepare crystals?

Answer 5

1) vapor diffusion (hanging drop)
- solvent molecules from the drop evaporate into the air, causing the concentration of the protein to increase
- reservoir solution diffuses into the droplet, changing its composition and creating a controlled environment for crystal growth
2) Sitting drop

Question 6

What are the crystal properties?

Answer 6

Multiple crystalline forms, significant water content, proteins retain functions in the crystal