Detailed Explanation
Technique for determining the three-dimensional atomic structure of peptides and proteins by diffracting X-rays through a crystallized sample. The diffraction pattern is mathematically transformed (Fourier transform) to generate an electron density map, from which the positions of individual atoms are determined.
Resolution is measured in angstroms (Å): <2.0 Å reveals individual atoms, 2.0–3.0 Å shows side chains clearly, >3.0 Å shows overall fold but not atomic detail. X-ray crystallography has determined the structures of most known proteins, including insulin (Dorothy Hodgkin, 1969), the ribosome (Nobel 2009), and thousands of drug-target complexes in the Protein Data Bank (PDB, >200,000 structures). The main limitation is that the protein must be crystallized — not all peptides form suitable crystals.
Key Facts
- Technique for determining the three-dimensional atomic structure of peptides and proteins by diffracting X-rays through a crystallized sample.
- The diffraction pattern is mathematically transformed (Fourier transform) to generate an electron density map, from which the positions of individual atoms are determined.
- Resolution is measured in angstroms (Å): <2.0 Å reveals individual atoms, 2.0–3.0 Å shows side chains clearly, >3.0 Å shows overall fold but not atomic detail.
- X-ray crystallography has determined the structures of most known proteins, including insulin (Dorothy Hodgkin, 1969), the ribosome (Nobel 2009), and thousands of drug-target complexes in the Protein Data Bank (PDB, >200,000 structures).
- The main limitation is that the protein must be crystallized — not all peptides form suitable crystals.
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PeptideDefinition.com provides educational content about peptide science. Not medical advice. Consult a licensed healthcare provider for medical decisions.