This popup provides the user a graphical representation of reference chemical shift data for proteins, RNA and DNA. Comparison of observed chemical shifts and these reference chemical shifts allows prediction of spin system types and secondary structure (e.g. alpha-helix or beta-sheet in proteins), using the Resonance: Spin System Types and the Spin System Type Scores popups.

The Resonance: Reference Chemical Shifts popup.

Molecule Type

Specifies the molecule type for which reference chemical shift graphs are displayed, with options:

• • protein

  • DNA

  • RNA

Ccp Code

Specifies the Ccp Code for the residue for which reference chemical shift graphs are displayed.

Atom Type

Specifies the atom type for which reference chemical shift graphs are displayed. The user can choose between:

• • Hydrogen

  • Heavy

atomSelector

The atom selector toolbar consists of a list of buttons for atom types that can be shown for a particular selection of molecule type, Ccp Code and Atom type. For example, for a protein Ala residue Hydrogens buttons are shown for H, HA and HB*.

scrolledGraph

This is the graph that shows the chemical shift distributions for the selected molecule type, residue type and atom types. The graph can be resized and various options to change the appearance and print are accessible through the right mouse menu. The graph is of the type Columns Graph.