Fig. 1: Mapping and bead chemical types of the Martini 3 protein model.
From: GōMartini 3: From large conformational changes in proteins to environmental bias corrections

The colors indicate the main classes of bead chemical types: P (polar, in red), N (intermediately polar, in blue), C (nonpolar, in gray), and Q (charged, in green). Different bead sizes are also indicated, ranging from the bead with the largest radii (regular, no symbol) to small (S) and tiny (T) beads.