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Glycan Cartoons in Byos

  • Updated

Understanding the glycosylation of therapeutic proteins is crucial for ensuring their safety and efficacy. For this reason, glycans and glycopeptides are both widely used as product quality attributes.


Byos supports characterisation of glycosylation at the intact, subunit, peptide, and released glycan level. Furthermore, the peptide and released glycan workflows now include structural information in the form of glycan cartoons that can be accessed at both project inspection and reporting steps.

Glycan cartoons in the released glycan workflows

The released glycan workflows facilitate identification of labelled glycans based on their mass. Identification is enabled using glycan libraries contained within the software. From Byos V4.4 users can include glycan cartoons as peak labels and in reports. These cartoons or structures are automatically displayed based on identifications made and associated with the internal library.

To enable this function the following advanced command should be entered:

[Plot]
EnableGlycanCartoons=true
GlycanCartoonsSymbolSize=6

EnableGlycanCartoons displays the peak labels as glycan cartoons. The size of the glycan cartoons can be controlled with the GlycanCartoonsSymbolSize parameter. The default size is 4.

This can be added at project creation (in processing nodes tab – advanced section) or in the project by selecting the advanced configuration option (as shown below):
The user has the option to choose from alternative representations of selected glycan structures by right clicking on a candidate that has a glycan composition, which will provide the option to Show alternative glycan structures.
Selecting this option opens a Glycan Structure Selection window allowing the user to choose between a list of structures that are contained in the library and match the glycan composition. The example below shows that in addition to the G1F structure for HexNAc(4)Fuc(1)Hex(4), there are several other options that the user can display.
If the user selects one of these alternatives and clicks OK, the structure shown in the chromatogram and reports will update to the user selection.

Structures included in the table are maintained in a library, but a user can add additional structures by clicking Add new from IUPAC. Selecting Add new from IUPAC opens a new window where the user can provide a text representation of the glycan structure in condensed IUPAC format. Once added these new structures will be available in the local library located at the following path:

C:\Users\[username]\AppData\Local\Protein Metrics\GlycanCartoonLibrary.csv

This copy is local to the user and can be updated with custom glycans.


It’s also possible to encode fine structural detail including linkage information using the IUPAC code. More details on inserting and customizing glycan cartoons can be found in the manual.

The glycan cartoon can be easily viewed in the report by selecting the option from the left-hand column pre-sets:
Glycan cartoons in the peptide workflows

Glycan cartoons are also available in the peptide workflows for annotating glycopeptide assignments. The available structures can be accessed from the peptide table by right clicking over the assignment and choosing one of the available options or adding an IUPAC string (as in the released glycan workflow).
In the peptide workflows the structures may be viewed in the report. To add this to the report, select Presets >> Pre pivot columns >> GlycanCartoon.prepvtjs
Once chosen and named, the new column option will appear in the available list on the left and can be selected by moving into the middle column:

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