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Assignment Statistics Tables

Assignment Statistics Tables

The assignment statistics tables can be calculated using a CCPN macro. Go to Macro / Run CCPN Macros / assignmentStatisticsTables. Select the Chain and Chemical Shift List for which you want to calculate your statistics. Tick the types of table you want to produce (see below for a description of each of these) and if you wish, change the names you give the tables. The macro will then produce your tables which you will find in the DataTables section of the sidebar. A timestamp is added to the table name. Simply drag the tables into the Drop Area to open and inspect them.

The tables provide various statistics about the degree of assignment of a protein Chain in your project. You can use this information to:

Please note: Certain atom groups are excluded from this analysis on the grounds that they are not normally assigned. The Biomolecular NMR Assignments journal would not typically expect you to report these as assigned, i.e. your protein can count as 100% assigned, even when these groups are not assigned. These groups are: carbon atoms with no attached protons (e.g. Phe/Tyr/Trp/His/Asp/Asn Cγ or Glu/Gln Cδ), OH/SH protons (e.g. Ser/Thr side chain OH or Cys SH protons), Lys side-chain Nζ groups, Arg side-chain Nε, Cζ and Nη groups, N-terminal amide groups.

Assigned Chemical Shifts Table

This table gives an overview of every assigned chemical shift in a chemical shift list for every possible atom or atom group in the selected chain. Consequently, this is a very large table with a very large number of columns.

Possible values:

Remember that you can exclude columns from the table by right-clicking on a Column header and selecting Column Settings.... You can also use the shortcut FT (or right-click in the table and select Filter...) to bring up the table filtering tool to look for particular rows you might be interested in (e.g. you could exclude PRO or search for rows with a - etc.). This table can be very useful for producing a table of chemical shifts to put into a paper or share with a colleague.

Assignment Completeness Table

This table provides an overview of which atom groups are assigned. Whereas the Assigned Chemical Shifts table lists all atoms separately, here they are grouped into HA, HB, CG etc. regardless of how many atoms may be part of that group.

Possible values:

Summary Assignment Table

This table provides a list of atom types (again grouped as HA, HB, CG etc.) and their percentage assignment coverage.

Possible values:

Possible Problems Table

This table only lists residues, for which the number of recorded chemical shifts falls outside the expected number. For instance, if an Ile γ proton has been recorded for HG1x but not for HG1y, this is listed in the HG column as 0.5.
NOTE: currently we do not catch errors such as inconsistent assignments, for instance if Ile HG1y and HG12 are both assigned then this will return 1.0

Possible values: