The present invention discloses methods and compositions comprising a novel expression cassette providing significantly improved levels of accumulation of Coleopteran inhibitory Cry3B variant protein when expressed in maize plants. The preferred embodiments of the invention provide at least up to ten fold higher levels of insect controlling protein relative to the highest levels obtained using prior compositions. In particular, transgenic maize expressing higher levels of a protein designed to exhibit increased toxicity toward Coleopteran pests deliver superior levels of insect protection and are less likely to sponsor development of populations of target insects that are resistant to the insecticidally active protein.