Resolution: Difference between revisions
From Proteopedia
Jump to navigationJump to search
Eric Martz (talk | contribs) No edit summary |
Eric Martz (talk | contribs) No edit summary |
||
| Line 35: | Line 35: | ||
Resolution is the smallest distance between crystal lattice planes that is resolved in the diffraction pattern. High numeric values of resolution, such as 4 Å, mean poor resolution, while low numeric values, such as 1.5 Å, mean good resolution. | Resolution is the smallest distance between crystal lattice planes that is resolved in the diffraction pattern. High numeric values of resolution, such as 4 Å, mean poor resolution, while low numeric values, such as 1.5 Å, mean good resolution. | ||
'''2.05 Å''' is the '''median''' resolution for [[X-ray crystallography|X-ray crystallographic]] results in the Protein Data Bank ( | '''2.05 Å''' is the '''median''' resolution for [[X-ray crystallography|X-ray crystallographic]] results in the Protein Data Bank (135,762 on May 19, 2019). For comparison, the van der Waals diameter of a carbon atom is 3.4-3.7 Å<ref name="atomsize">See [http://en.wikipedia.org/wiki/Atomic_radii_of_the_elements_(data_page) Atomic radii of the elements (Wikipedia)], and [http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Chemical_Bonding/General_Principles/Covalent_Bond_Distance,_Radius_and_van_der_Waals_Radius values from an Inorganic Chemistry textbook].</ref>, and the length of a covalent carbon-carbon bond is 1.5 Å<ref name="atomsize" />. | ||
If some portions of the macromolecule are less ordered in the crystal than others, these will have a poorer resolution. The "resolution of the crystal" represents the most ordered portions (see [[#Determination of Resolution|Determination of Resolution]]). | If some portions of the macromolecule are less ordered in the crystal than others, these will have a poorer resolution. The "resolution of the crystal" represents the most ordered portions (see [[#Determination of Resolution|Determination of Resolution]]). | ||
