In this work, we present a theoretical and numerical analysis of the vibrational coupling of two deuterated structural elements in proteins. Depending on the presence and magnitude of coupling between these elements, typically deuterium atoms connected to alpha carbons, characteristic level splittings of vibrational eigenstates are predicted, which are observable around 2100 cm(-1) in a broad and transparent spectral window. This approach is illustrated and substantiated by the application of classical force fields to the simulation of the vibrational density of states of the crambin protein. We discuss the possibility to use this effect to obtain structural information about proteins and suggest experiments to verify our theoretical approach.