Dear All

I tried to group atoms of acetylcholine into beads by following the Martini tutorial for parametrizing new molecule. It is recommended to group them based on the building blocks in Table 3 of their publication in 2007. Following their suggestion, I divided acetylcholine into two main regions ; choline (C3N+) and glycerol ester (C-O-C=O). However, there are still -CH2 group left between the chain and -CH3 group left at the end of molecule. How can I group these two left groups since it is suggested to do 4 to 1 mapping?

Best Regards

Phakawat