Noncommutative of space-time and the relativistic Hydrogen atom

We study the Klein-Gordon equation in a non-commutative space-time as applied to the Hydrogen atom to extract the energy levels, by considering the second-order corrections in the non-commutativity paramete and by comparing to the 2S - 1S transition accuracy we get a bound on the parameter of noncommutativity. Phenomenologically we show that non-commutativity is the source of lamb shift corrections and spin electron.