Glycan Composition Calculator

This application calculates which combinations of fucose (146 Da), β-mannose (162 Da), and NAG (203 Da) glycans are needed to explain the difference in glycoprotein mass as a result of N-linked glycosylation from insect cells.

Real-life example

• A biochemist conducts a mass spectrometry experiment on a glycoprotein that was purified from Sf9 insect cells. In addition to the predicted native protein mass, a significant peak of +1184 Da is observed. What is it?
• Using the Glycan Composition Calculator and an input of 1184, we learn that the modification comes from 2 NAG, 3 mannose, and 2 fucose residues.
• With this knowledge, the biochemist can select the appropriate strategy for deglycosylating the glycoprotein.

How to use it

Grab the release for your operating system from the ‘Releases’ tab and extract the archive.

Given the example data above, run ./glycan 1184.

Sample Output

$ ./glycan 1184
Input Value: 1183 (Adjusted by -1):
Fucose    Mannose    NAG
------    -------    ---
Input Value: 1184 (Adjusted by +0):
Fucose    Mannose    NAG
------    -------    ---
2    3    2
7    1    0
Input Value: 1185 (Adjusted by +1):
Fucose    Mannose    NAG
------    -------    ---

By default it’ll bracket the input by 1 Da, printing results for (input-1) and (input+1) as well. This may be useful if your measurements include some margin of error, as the sample one does. You can increase or decrease the bracketing margin with the -b flag. Passing -b 0 will disable bracketing entirely.

Caveats

It could almost certainly be more efficient, and there might be bugs and edge cases. If you find one, please report it!