A note on two-spin magnon-like energy-charge relations from M-theory   viewpoint
  We show that for each M-theory background, having subspaces with metrics of given type, there exist M2-brane configurations, which in appropriate limit lead to two-spin magnon-like energy-charge relations, established for strings on AdS_5 x S^5, its beta-deformation, and for membrane in AdS_4 x S^7. 
P. Bozhilov