L41 BIOL 4810 Lecture Notes - Lecture 18: Heteronuclear Single Quantum Coherence Spectroscopy, The Molecules, Phase Problem
12 May 2020
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Document Summary
Crystallography in 5 steps: purify protein, grow crystals, x-ray diffraction data, phasing the structure, building and refining the model. Diffraction pattern results from crystal lattice: as a group of molecules gets more and more ordered, they form a diffraction pattern, the molecules must be ordered to produce a distinct pattern! Obtaining diffraction data: x-ray generators, synchrotron, particle accelerator, x-ray intensity is greater, can collect more data in a shorter time period. Collecting diffraction data: resolution: minimum, minimum distance between any two things you can differentiate, how many data points you collect, more points = more data, lower number = higher resolution. Collecting diffraction data: the practical meaning of resolution, more data means better model, left = lower res data (higher number, right = high res data (lower number) This commonly done by replacing methionine with seleno-methionine when producing the protein (aka molecular biology and heterologous expression is needed!: newest method. Stacking of the electron density may begins to give contours.
