GO:0090560:   2-(3-amino-3-carboxypropyl)histidine synthase activity
Catalysis of the reaction S-adenosyl-L-methionine + L-histidine-[translation elongation factor 2] = S-methyl-5-thioadenosine + 2-[(3S)-3-amino-3-carboxypropyl]-L-histidine-[translation elongation factor 2].