Asymmetric Unit: Difference between revisions

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* <scene name='Asymmetric_Unit/Unit_cell/5'>Unit Cell</scene>. In the case of [[2qcb]], the unit cell contains portions of 16 copies of the asymmetric unit.

The '''asymmetric unit''' is the smallest portion of a crystal that~~, when~~ duplicated and moved by crystal symmetry operations, can ~~produce~~ the unit cell of the crystal. The symmetry operations that are common for biological molecules are rotation, translation, and screw operations (which combine rotation and translation). Mirror symmetry planes occur rarely in crystals of biological molecules due to the presence of chiral centers, e.g. L or D amino acids.

The '''asymmetric unit''' is the smallest portion of a crystal that provides a complete solution. When duplicated and moved by crystal symmetry operations, the unit cell of the crystal can be generated, and from the unit cell, large portions of the crystal. The symmetry operations that are common for biological molecules are rotation, translation, and screw operations (which combine rotation and translation). Mirror symmetry planes occur rarely in crystals of biological molecules due to the presence of chiral centers, e.g. L or D amino acids.

The '''[[Biological Unit|biological unit]]''' is defined elsewhere.

The '''unit cell''' is the smallest portion of a crystal that, when duplicated and translated, can generate the entire crystal. ~~You~~ can '''see the unit cell''' by clicking on the ~~word ''Jmol'' to the lower right of any molecular display~~ in ~~Jmol (which includes most interactive molecular displays in Proteopedia)~~, and then on the menu that appears, Style, ~~then check the~~ Unit Cell ~~checkbox~~. You can populate the unit cell from Jmol's menu with Symmetry, Reload {1 1 1}.

The '''unit cell''' is the smallest portion of a crystal that, when duplicated and translated, can generate the entire crystal.

<font color="gray">If the green link "Unit Cell" above is not working, you can '''see the unit cell''' by right-clicking on the molecule in JSmol, and then on the menu that appears,

Symmetry, Reload {1 1 1}.</font>

</blockquote>

==Websites==

*Diagrams illustrating these concepts are available at the [~~http~~://~~www~~.rcsb.org/~~robohelp~~/~~data_download~~/~~biological_unit/asymmetric_unit.htm~~ RCSB Protein Data Bank].

*Diagrams illustrating these concepts are available at the [https://pdb101.rcsb.org/learn/guide-to-understanding-pdb-data/biological-assemblies RCSB Protein Data Bank].

*[http://www.usm.maine.edu/~rhodes/ModQual/ Glossary of Terms from Crystallography, NMR, and Homology Modeling]

*[http://reference.iucr.org/dictionary/Asymmetric_unit Asymmetric unit] at the [http://reference.iucr.org/dictionary/Main_Page Online Dictionary of Crystallography] of the International Union of Crystallographers.

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@@ Line 9: / Line 9: @@
 * <scene name='Asymmetric_Unit/Unit_cell/5'>Unit Cell</scene>. In the case of [[2qcb]], the unit cell contains portions of 16 copies of the asymmetric unit. <!--<font color="red">Sorry, still not working. See instructions below.</font>-->
-The '''asymmetric unit''' is the smallest portion of a crystal that, when duplicated and moved by crystal symmetry operations, can produce the unit cell of the crystal. The symmetry operations that are common for biological molecules are rotation, translation, and screw operations (which combine rotation and translation). Mirror symmetry planes occur rarely in crystals of biological molecules due to the presence of chiral centers, e.g. L or D amino acids.
+The '''asymmetric unit''' is the smallest portion of a crystal that provides a complete solution. When duplicated and moved by crystal symmetry operations, the unit cell of the crystal can be generated, and from the unit cell, large portions of the crystal. The symmetry operations that are common for biological molecules are rotation, translation, and screw operations (which combine rotation and translation). Mirror symmetry planes occur rarely in crystals of biological molecules due to the presence of chiral centers, e.g. L or D amino acids.
 The '''[[Biological Unit|biological unit]]''' is defined elsewhere.
-The '''unit cell''' is the smallest portion of a crystal that, when duplicated and translated, can generate the entire crystal. You can '''see the unit cell''' by clicking on the word ''Jmol'' to the lower right of any molecular display in Jmol (which includes most interactive molecular displays in Proteopedia), and then on the menu that appears, Style, then check the Unit Cell checkbox. You can populate the unit cell from Jmol's menu with Symmetry, Reload {1 1 1}.
+The '''unit cell''' is the smallest portion of a crystal that, when duplicated and translated, can generate the entire crystal.
+<blockquote>
+<font color="gray">If the green link "Unit Cell" above is not working, you can '''see the unit cell''' by right-clicking on the molecule in JSmol, and then on the menu that appears,
+<!--Style, Unit Cell, On. You can populate the unit cell from Jmol's menu with -->
+Symmetry, Reload {1 1 1}.</font>
+</blockquote>
 ==Websites==
-*Diagrams illustrating these concepts are available at the [http://www.rcsb.org/robohelp/data_download/biological_unit/asymmetric_unit.htm RCSB Protein Data Bank].
+*Diagrams illustrating these concepts are available at the [https://pdb101.rcsb.org/learn/guide-to-understanding-pdb-data/biological-assemblies RCSB Protein Data Bank].
 *[http://www.usm.maine.edu/~rhodes/ModQual/ Glossary of Terms from Crystallography, NMR, and Homology Modeling]
 *[http://reference.iucr.org/dictionary/Asymmetric_unit Asymmetric unit] at the [http://reference.iucr.org/dictionary/Main_Page Online Dictionary of Crystallography] of the International Union of Crystallographers.