MarvinSketch enables you to view and manipulate the source of any supported file formats.
Molecules can be changed by editing their source in the Source window ( Edit > Source menu option).
To change format of source, simply select the desired one from the View menu.
If there are multiple molecules on the canvas, checking View as multiple molecules in the View menu leads to each molecule appearing in a separate block in the source.
This feature works only, if the selected format is able to handle multiple structures.
To reload the molecule into canvas (including any changes you may have made), select File > Import As.
If the automatic format recognition detects a file format (checking it by a priority list), it will be offered in the Select Import Mode field (Import as Recognized, indicating the file type in brackets).
If the structure is associated to a file type of higher priority than your choice, choose the Import As option to set the file format.
For example, you want to import the seryl-asparagine dipeptide:
write "SN" in the Source
select Import. The automatic option detects it as SMILES, but if you select the Import As option, and then the 'Peptide Sequence' from the list, it will be imported correctly.
In addition, there are some cases when the automatic recognition cannot detect the file format, even though the entered text is correct. In this case the Import As Recognized option is disabled and you have to choose the format from the list of the Import As option.