RetroPath2.0 algorithm as a standalone application aimed to be easy to use and install.

The algorithm builds a reaction network from a set of source compounds to a set of sink compounds using a set of reaction rules. In retrosynthesis the source is (are) the target compound(s) and sink are the native metabolites. After generating the chemical reactions via retrosynthesis a subset may effectively link a source to a subset of sink compounds. This sub-network is a scope and is output in a dedicated file. (Delépine et al., 2018)

• Windows 10 x64 and Windows 11 x64
• macOS Big Sur or newer on the Apple Silicon architecture (M1/M2 Macs); Intel Macs are not supported at present.
• Linux x64 (tested on Ubuntu)

1. Open GitHub Releases in a new tab (so you can easily go back to this document and reference further instructions) and download the distribution for your operating system by expanding the Assets list and downloading the file for your operating system.

2. Unzip the downloaded file by right clicking on the file and selecting "Extract All" and following the extraction wizard. If you get an error due to permissions/security exit the wizard, right click on the file, click "Properties" and towards the bottom right select "Unblock". You can see a visual example how to do it here.

2. Open the terminal, cd into the folder where the downloaded zip file is and type unzip file_name.zip replacing file_name with the name of the downloaded file.

3. Give RetroPath the permission to execute by cding into the unzipped folder in the terminal and running chmod +x ./RetroPath.Cli.

2. Unzip the downloaded file by double clicking the zip file.

3. Go to the download page for .NET 6 by opening this link in a new tab [1].

4. On the right side find the position that says ".NET Runtime", then find macOS in the table in the Installers column and click on "Arm64" to download the installer. This will download the ".pkg" installer.

5. Open the downloaded installer and follow the instructions to complete the installation of .NET 6 Runtime.

^{[1] - .NET runtime has to be separately installed on macOS because macOS requires all pre-compiled binaries to be signed using an Apple Developer account which costs £100/year, to avoid that charge the RetroPath binaries for macOS are distributed as framework-dependant as the .NET runtime is already signed by Microsoft.}

Bundled with the program is a simple pinocembrin example data to verify the installation works.

1. Enter the unzipped folder and open the terminal (On Windows 11 you can open the terminal inside the folder by right clicking inside the folder and selecting "Open in terminal", otherwise open PowerShell and cd into the folder).

2. Run the following command via the terminal: ./RetroPath.Cli.exe "./example_data/rules.csv" "./example_data/source.csv" "./example_data/sink.csv" 4.

1. Enter the unzipped folder and open the terminal inside it (you can do this by opening the terminal and cding into the folder).

2. Run the following command via the terminal: ./RetroPath.Cli "./example_data/rules.csv" "./example_data/source.csv" "./example_data/sink.csv" 4

Linux-only caution: In the unlikely event that some system package is missing a human readable exception will be thrown and you should read it to see what package is missing and then install the missing package from your distro's package maneger (e.g. apt/yum/etc.).

1. Enter the unzipped folder and open the terminal inside it (you can do this by opening the terminal and cding into the folder).

2. Run the following command via the terminal: dotnet RetroPath.Cli.dll "./example_data/rules.csv" "./example_data/source.csv" "./example_data/sink.csv" 4.

IMPORTANT: If while running the program you get a pop-up saying "RDKFuncs.so can't be opened because Apple can't check it for malicious software" click "Ok". This will make the program quit with an error. This file is the library for the RDKit cheminformatics suite and can safely be opened, however it is not signed due to the aforementioned £100/year account requirement. To allow macOS to run it, immediately after the program quits with an error open System Preferences -> Security & Privacy. Towards the bottom there should be "RDKFuncs.so was blocked from use because it is not from an identified developer". Click "Allow anyway". Now run the command from step 2 again and when the pop up pops up again there will be a new option "Open". Click it. This will allow the program to execute correctly.

To view the results see the results folder that has been generated after running the example. Inside the folder there should be a results.csv file with the generated global results. Open it in Excel or equivalent software (e.g. LibreOffice Calc). Inside the file there should be 6 results (not counting the header with the column names) with Initial source being [pinocembrin] for each. The last column should be Iteration. If you have got such results then they are correct.

To see help how to use the program with all the possible options and parameters run ./RetroPath.Cli on Linux/macOS and ./RetroPath.Cli.exe in the terminal.

The basic usage is ./RetroPath.Cli <rules-file> <source-file> <sink-file> <pathway-length>. On Windows ./RetroPath.Cli needs to be replaced with ./RetroPath.Cli.exe and on macOS with dotnet RetroPath.Cli.dll.

TODO

Delépine, B., Duigou, T., Carbonell, P. and Faulon, J.-L. (2018). RetroPath2.0: A retrosynthesis workflow for metabolic engineers. Metabolic Engineering, 45, pp.158–170. doi:10.1016/j.ymben.2017.12.002. ‌