Novel insect inhibitory proteins are disclosed comprising two different components, both of which are required for biological activity. Various methods of linking both components together, so that a single protein provides insect inhibitory activity, are disclosed. Also disclosed are novel Bacillus thuringiensis nucleic acid sequences encoding Coleopteran-inhibitory crystal proteins, designated tIC100 (29-kDa) and tlC101 (14-kDa). Also disclosed are methods of making and using nucleic acid sequences in the development of the transgenic plant cells containing the novel nucleic acid sequences disclosed herein.