De Novo Settings
Precursor Mass Tolerance
The precursor mass tolerance can be set between 0 and 5.0 Da.
Fragment Mass Tolerance
The fragment mass tolerance can be set between 0 and 0.75 Da.
No. Solutions
This parameter presents the number of possible peptide suggestions for each spectrum (1-20).
The default setting is 20 solutions.
No. Threads/Cores
The number of threads is given by the number of available CPU cores by default.
This parameter is important to speed up the de novo sequencing.
Use Spectrum Precursor m/z
When activated, the given spectrum precursor m/z is used and no correction for the spectrum precursor m/z is executed.
This setting is disabled by default.
Use Spectrum Charge
When activated, the given spectrum charge is used and no correction for the spectrum charge is executed.
This setting is disabled by default.
Modifications
There are two types of modifications, fixed and variable. Fixed modifications will
be added to every residue that can be modified by the given modification, while the variable modifications
are sometimes added and sometimes not. Which type to choose depends on your experimental setup.
You can add multiple modifications of each type, but remember that the more variable modifications you
add the more complex the search becomes which increases the risk of false positives.
Initially only the most used modifications are shown. To show all modifications simply select 'All
Modifications' in the drop down menu above the list of modifications. Here you can also see more
details about each modification.
Note that PepNovo+ does not support fixed modifications on the terminals, and these will therefore be
treated as variable.
De Novo Model
PepNovo+ has been trained using a dataset based on
tryptic peptides using CID fragmentation, but should also work reasonably well for other data types. While it is
possible to train PepNovo+ using other dataset the procedure is rather complicated. If you want to support other
data types we therefore recommend contacting the PepNovo+ developers.