Jan 24 Flashcards
How are reciprocal unit cells drawn?
Draw line perpendicular to that particular plane and the length of this line is 1/interplanar spacing for that set of planes
What is sphere of reflection, what do for us?
Radius is 1/wavelength of xrays used. Any point on sphere meets reciprocal lattice, get diffraction conditions. Crystal in centre of sphere. We derived Bragg’s Law from it.
Rotate crystal means we rotate the lattice and get other nodes from lattice to touch edge of sphere.
Instead of rotating crystal to get other reciprocal space lattice nodes to be in diffraction conditions, what else could you do?
Change the wavelength, so like sphere of reflection, you change radius (1/wavelength), so it touches different points of lattice
Can you have symmetry mirror and rotation plane at once with proteins?
No you can’t, only one at once. If you have both, then you would need to have all the AA’s to be R-handed not L-handed to give you the same protein molecule.
