X-ray Crystallography Lecture Notes

These flashcards cover key vocabulary and concepts related to X-ray crystallography and protein structure determination.

X-ray Crystallography

A method used to determine the atomic and molecular structure of a crystal by scattering X-rays off of the crystal's lattice.

Protein structure determination methods

Techniques used to reveal the three-dimensional arrangement of atoms in proteins, with X-ray crystallography being a prominent method.

Electron density map

A three-dimensional representation of the distribution of electron density within a crystal, used to infer the positions of atoms.

Unit cell

The smallest repeating unit in a crystal lattice that contains at least one protein molecule.

Crystallization

The process of forming a solid crystal from a solution, which is a crucial step in X-ray crystallography.

Bragg's Law

A fundamental equation that describes how X-rays are diffracted by the crystal lattice, given by the equation $ext{λ} = 2d_{hkl} ext{sin}( heta)$.

Phase problem

A challenge in X-ray crystallography where the phase information of scattered X-rays is lost and needs to be recovered.

Molecular replacement

A method used to determine the phases in X-ray crystallography by using the known structure of a similar protein.

MAD (Multiple Anomalous Dispersion)

A technique that requires synchrotron radiation to collect data at different wavelengths to solve the phase problem.

MIR (Multiple Isomorphous Replacement)

A method for solving the phase problem by soaking crystals in heavy atom solutions to observe differences in diffraction.

Protein Data Bank (PDB)

A repository for three-dimensional structural data of biological molecules, including proteins and nucleic acids.