Model of the hepatitis B virus (Dane particle) and the filamentous or spherical HBsAg particles. Dane described the virus as 42 nm particle but in the negative staining the outer preS1 and preS2 domains were not visible. 52 nm is the hydrodynamic diameter (Ch. Schüttler and W. Gerlich, unpublished) and also measured by cryo-EM as the outer diameter , suppl. Figure 2. HBsAg protein comes in three forms: large (L-) HBs protein with the preS1, preS2 and S domain, middle protein (M-) without preS1 and SHBs without preS1 and preS2.